This document outlines the key objectives and concepts covered in a chapter on light and atomic structure. It begins by listing the chapter objectives, which include describing properties of light as waves, explaining the photoelectric effect using a photon model of light, relating atomic spectra to quantized energy levels of atoms, and describing atomic structure using the Bohr and quantum mechanical models. It then provides explanations and examples to achieve these objectives, covering topics like the electromagnetic spectrum, wave properties of light, the particulate nature of light demonstrated by the photoelectric effect, atomic spectra, and atomic structure models. Diagrams and example problems are included to illustrate the concepts.
1) The document discusses the electronic structure of atoms, beginning with a description of the electromagnetic spectrum and wave-particle duality of light. 2) It then covers early atomic models including Planck's quantum theory, Bohr's model of the atom, and de Broglie's proposal that electrons exhibit wave-like properties. 3) The document concludes by mentioning the development of quantum mechanics and Heisenberg's uncertainty principle.
The document discusses electrons in atoms and their arrangement. It begins by explaining the wave-particle duality of light and electrons. It then discusses the historical atomic models of Rutherford, Bohr, and the quantum mechanical model. The quantum mechanical model treats electrons as waves and describes their location in terms of probability distributions within orbitals. The document concludes by explaining the rules that determine electron configuration, including the Aufbau principle, Pauli exclusion principle, and Hund's rule.
Electrons are important because their wavelike properties help explain atomic structure and spectra. Electrons can only gain or lose energy in specific quantized amounts called quanta. The quantum mechanical model treats electrons as waves and uses probability maps instead of fixed orbits, with electrons located in regions called atomic orbitals based on their quantum numbers.
The document provides a history of the development of atomic structure models from ancient Greek philosophers' ideas of indivisible atoms to the modern quantum mechanical model. It describes key experiments and findings such as Thomson's discovery of electrons, Rutherford's gold foil experiment, and Bohr's model of electron orbits that led to modern atomic theory. The emission spectra of elements provided evidence that electrons exist in specific energy levels and orbitals within atoms.
The document discusses the discovery and evolving models of the electron. [1] Early experiments showed the electron is a negatively charged, virtually massless particle within atoms. [2] However, the Rutherford model could not explain how atoms avoid collapse or different elemental properties. [3] Quantum theory resolved this by proposing the electron acts as both a particle and wave, occupying discrete energy levels and absorbing/emitting photons when changing levels.
Radiation comes in many forms and can be classified as ionizing or non-ionizing. Ionizing radiation has enough energy to remove electrons from atoms and includes gamma rays, X-rays, and alpha/beta particles. Non-ionizing radiation does not have enough energy to ionize atoms and includes visible light, microwaves, and radio waves. Radiation is measured in units like the curie and becquerel that represent radioactive decays, while exposure is measured in rads and grays representing absorbed energy doses. Radiation finds many uses in fields like medical imaging and treatment.
This document discusses the development of atomic models. It describes properties of light including its wave-particle duality. The photoelectric effect and hydrogen's emission spectrum provided evidence that light behaves as particles (photons) as well as waves. Max Planck proposed that light energy is quantized in units of hf, where h is Planck's constant and f is the photon's frequency. Niels Bohr's model of the hydrogen atom explained its emission spectrum by proposing that electrons can only orbit at certain distances corresponding to specific energy levels, emitting or absorbing photons as they transition between levels.
Module01 nuclear physics and reactor theorysirwaltz73
This document provides an overview of a basic professional training course on nuclear physics and reactor theory. It covers topics like atomic structure, the structure of the atom including electrons and the nucleus, isotopes, radioactive decay, and nuclear reactions. The document is divided into several modules, with learning objectives provided for each section. It includes diagrams and examples to illustrate key concepts in nuclear physics.
1) The document discusses the electronic structure of atoms, beginning with a description of the electromagnetic spectrum and wave-particle duality of light. 2) It then covers early atomic models including Planck's quantum theory, Bohr's model of the atom, and de Broglie's proposal that electrons exhibit wave-like properties. 3) The document concludes by mentioning the development of quantum mechanics and Heisenberg's uncertainty principle.
The document discusses electrons in atoms and their arrangement. It begins by explaining the wave-particle duality of light and electrons. It then discusses the historical atomic models of Rutherford, Bohr, and the quantum mechanical model. The quantum mechanical model treats electrons as waves and describes their location in terms of probability distributions within orbitals. The document concludes by explaining the rules that determine electron configuration, including the Aufbau principle, Pauli exclusion principle, and Hund's rule.
Electrons are important because their wavelike properties help explain atomic structure and spectra. Electrons can only gain or lose energy in specific quantized amounts called quanta. The quantum mechanical model treats electrons as waves and uses probability maps instead of fixed orbits, with electrons located in regions called atomic orbitals based on their quantum numbers.
The document provides a history of the development of atomic structure models from ancient Greek philosophers' ideas of indivisible atoms to the modern quantum mechanical model. It describes key experiments and findings such as Thomson's discovery of electrons, Rutherford's gold foil experiment, and Bohr's model of electron orbits that led to modern atomic theory. The emission spectra of elements provided evidence that electrons exist in specific energy levels and orbitals within atoms.
The document discusses the discovery and evolving models of the electron. [1] Early experiments showed the electron is a negatively charged, virtually massless particle within atoms. [2] However, the Rutherford model could not explain how atoms avoid collapse or different elemental properties. [3] Quantum theory resolved this by proposing the electron acts as both a particle and wave, occupying discrete energy levels and absorbing/emitting photons when changing levels.
Radiation comes in many forms and can be classified as ionizing or non-ionizing. Ionizing radiation has enough energy to remove electrons from atoms and includes gamma rays, X-rays, and alpha/beta particles. Non-ionizing radiation does not have enough energy to ionize atoms and includes visible light, microwaves, and radio waves. Radiation is measured in units like the curie and becquerel that represent radioactive decays, while exposure is measured in rads and grays representing absorbed energy doses. Radiation finds many uses in fields like medical imaging and treatment.
This document discusses the development of atomic models. It describes properties of light including its wave-particle duality. The photoelectric effect and hydrogen's emission spectrum provided evidence that light behaves as particles (photons) as well as waves. Max Planck proposed that light energy is quantized in units of hf, where h is Planck's constant and f is the photon's frequency. Niels Bohr's model of the hydrogen atom explained its emission spectrum by proposing that electrons can only orbit at certain distances corresponding to specific energy levels, emitting or absorbing photons as they transition between levels.
Module01 nuclear physics and reactor theorysirwaltz73
This document provides an overview of a basic professional training course on nuclear physics and reactor theory. It covers topics like atomic structure, the structure of the atom including electrons and the nucleus, isotopes, radioactive decay, and nuclear reactions. The document is divided into several modules, with learning objectives provided for each section. It includes diagrams and examples to illustrate key concepts in nuclear physics.
This document provides an overview of key concepts in nuclear physics covered in Chapter 43, including:
1) Properties of nuclei such as nucleon number, radius, density, isotopes, and nuclear magnetic moments.
2) Nuclear models including the liquid drop model and shell model to describe nuclear stability.
3) Nuclear binding energy and how it depends on proton and neutron numbers. The nucleus with the highest binding energy per nucleon is 62Ni.
4) Radioactivity and different types of nuclear decay processes, including alpha decay, beta decay, and gamma decay. Stable nuclides lie along an asymmetric line in the nuclear chart that favors more neutrons than protons for higher atomic masses.
1. The document discusses the early development of theories of light and quanta, including Planck's theory that energy can only be emitted or absorbed in discrete quanta and Einstein's proposal that light has particle-like properties as photons.
2. It explains how Bohr used Planck and Einstein's work to develop his quantum model of the hydrogen atom, which successfully explained the atomic emission spectrum of hydrogen.
3. De Broglie later proposed that all particles have both particle-like and wave-like properties, which provided an explanation for the fixed, quantized energy levels in Bohr's model of the hydrogen atom.
This document provides an overview of the principles of laser operation. It discusses:
- Laser cavities consisting of an amplifying medium between two mirrors that provide feedback.
- Fabry-Perot resonators and the standing wave patterns that form from interference between waves moving in opposite directions within the cavity.
- Population inversion being necessary for stimulated emission to exceed absorption, allowing amplification of light passing through the active medium.
- Optical pumping being used to invert the population by exciting atoms to a long-lived excited state, building up a population there.
- Stimulated emission causing photons to be emitted in phase with the stimulating photon, allowing amplification through an avalanche effect within the inverted medium.
The document summarizes key topics in the chapter on nuclear physics, including:
1) The structure and properties of the nucleus, including its composition of protons and neutrons.
2) The discovery of the neutron by James Chadwick in 1932, which helped explain nuclear structure.
3) The strong and weak nuclear forces that bind nucleons together in the nucleus.
Classical mechanics fails to explain several experimental observations such as:
1) Black-body radiation spectrum
2) Photoelectric effect
3) Compton scattering
4) Spectrum of hydrogen emissions
Quantum mechanics was developed to account for these phenomena by treating electrons as both particles and waves. Max Planck proposed quanta to explain black-body radiation, while Albert Einstein and Niels Bohr used quanta to explain the photoelectric effect and hydrogen spectrum respectively. Arthur Compton also explained Compton scattering using photons colliding with electrons.
This document provides an overview of radiation and ionizing radiation. It defines radiation as energy in the form of electromagnetic waves or particulate matter that travels through the air. It describes the basic particles that make up atoms - protons, neutrons, and electrons - and how atoms are composed. Unstable atoms emit radiation as they seek stability. There are various types of ionizing radiation, including alpha particles, beta particles, gamma rays, x-rays, and neutrons. Radiation exposure and dose are quantified, and biological effects of radiation at both the cellular level and for the human body are discussed. Controls for radiation include time, distance, and shielding to reduce exposure. Monitoring programs are also outlined.
The document summarizes Rutherford's alpha scattering experiment and its implications. It showed that atoms have small, dense nuclei containing their mass, surrounded by empty space. This contradicted the plum pudding model of atoms as diffuse positive charges. Later, Bohr proposed his model of electrons orbiting in discrete energy levels, explaining atomic spectra. However, it did not fully resolve issues like why electrons don't collapse into the nucleus.
Planck's Quantum Theory and Discovery of X-raysSidra Javed
Planck's quantum theory
Discovery of X-rays and explanation of production of X-rays, relation between atomic number and frequency of X-rays, application and uses of X-rays.
1. The document discusses the electronic structure of atoms, including the wave-particle duality of electrons.
2. It describes how electrons can only occupy certain quantized energy levels around the nucleus, and how electrons moving between these levels explains atomic emission spectra.
3. The key ideas of Planck, Bohr, de Broglie, and Heisenberg helped develop our modern understanding of electrons as behaving as both particles and waves simultaneously in atoms.
Nuclear physics involves different types of radioactive decays such as alpha decay where a nucleus loses two protons and two neutrons decreasing its atomic number by two and mass number by four, gamma decay where a nucleus in an excited state decays to a lower energy state by emitting a gamma ray photon without changing atomic or mass numbers, and decay series where a parent nucleus decays into one or more daughter nuclei through successive decays. Radioactive decay rates depend on factors like the strong and electromagnetic forces, and radioactive decay inside Earth from elements like uranium and thorium produces heat through high-energy particles, providing an internal heat source that has kept Earth's interior hotter than
This document discusses the wave-particle duality of light and matter. It explains how experiments demonstrating the photoelectric effect and electron diffraction show that electromagnetic radiation and electrons exhibit both wave-like and particle-like properties depending on the situation. De Broglie hypothesized that all particles can behave as waves, and he formulated an equation showing that particles are associated with a wavelength determined by their momentum and Planck's constant.
Atomic emission spectra and the quantum mechanical model Angbii Gayden
1) Atomic emission spectra provide evidence that electrons within atoms can only occupy discrete energy levels. When electrons drop from higher to lower energy levels, they emit photons of light at specific wavelengths, producing lines in the atomic emission spectrum.
2) Max Planck proposed that electromagnetic radiation like light is emitted and absorbed in discrete quanta of energy called photons, where the energy of each photon is directly proportional to its frequency.
3) Albert Einstein applied Planck's quantum theory to explain the photoelectric effect, proposing that light behaves as a particle as well as a wave, with a quantum of energy depending on its frequency.
Photoelectric Effect And Dual Nature Of Matter And Radiation Class 12Self-employed
This document discusses the photoelectric effect and the dual wave-particle nature of matter and light. It covers:
1) An overview of the photoelectric effect and how it demonstrated the particle nature of light via Einstein's photoelectric equation.
2) De Broglie's hypothesis that matter has wave-like properties described by the de Broglie wavelength.
3) Daviesson and Germer's experiment demonstrating the wave-like diffraction of electrons from a crystal lattice, verifying matter waves.
This document provides an overview of spectroscopy and how it can be used to determine the composition of astronomical objects. It discusses how light interacts with matter on an atomic level, causing absorption and emission spectra that act as "elemental barcodes." The spectra are caused by electrons transitioning between quantized energy levels in atoms and emitting or absorbing photons of specific wavelengths. Measuring the absorption lines in a star's spectrum allows astronomers to identify the elements present in a star's atmosphere and determine its chemical composition, such as the fact that hydrogen and helium make up over 97% of the Sun's mass.
Light interacts with materials through reflection, absorption, transmission, and refraction. When light passes from one medium to another, its speed changes, causing refraction. Reflection occurs at interfaces and depends on the refractive indices. Absorption is determined by electron transitions and occurs only for photon energies exceeding the band gap. Materials are classified as transparent, translucent, or opaque based on their transmission properties. The color of materials arises from wavelengths of light that are transmitted or re-emitted after absorption. Optical fibers use total internal reflection to transmit light signals over long distances.
Bohr's model of the atom proposed that electrons orbit the nucleus in fixed orbits and absorb or emit discrete amounts of energy when changing orbits. Later evidence showed electrons exist as a probabilistic electron cloud rather than fixed orbits. Atomic orbitals represent regions where electrons are most likely found and electrons occupy orbitals according to their electron configuration, which arranges them in the lowest energy state.
Electrons in Atoms can be summarized as follows:
1) Light exhibits both wave-like and particle-like properties, with electrons in atoms also displaying wave-like characteristics that help explain atomic structure.
2) Atoms are arranged according to a set of rules, with electrons occupying specific energy levels and orbitals around the nucleus according to the aufbau principle and other quantum rules.
3) The Bohr and quantum mechanical models both describe the discrete energy levels electrons can occupy in atoms, with the latter treating electrons as waves rather than fixed orbits and establishing probability distributions rather than precise paths.
Electrons are important because their arrangement in atomic orbitals determines an element's properties and reactions. Electrons exhibit both wave-like and particle-like behavior. According to quantum theory, electrons occupy specific atomic orbitals and energy levels. Their configuration is defined by rules like the Aufbau principle and Pauli exclusion principle. Valence electrons in the outermost shell determine an element's chemical behavior.
This document discusses the electronic structure of atoms. It begins by reviewing early atomic models proposed by Thomson, Rutherford, and Chadwick that included a dense nucleus surrounded by electrons. The document then discusses how quantum mechanics provides a better model of electronic structure through the use of orbitals and quantum numbers to describe allowed electron configurations. Key points covered include the wave-particle duality of electrons, Schrodinger's wave equation describing orbital shape and orientation, and the four quantum numbers (n, l, ml, ms) that provide unique descriptions of electron states.
1. The document provides an overview and review of topics covered on the AP Physics B exam related to modern physics, including the photoelectric effect, Bohr model of the atom, and nuclear physics.
2. It describes Einstein's explanation of the photoelectric effect involving photons and how it resolved issues not explained by classical wave theory.
3. It also explains the Bohr model of the hydrogen atom, including Bohr's assumptions and how it leads to quantized electron orbits that can explain atomic emission spectra.
The document discusses atomic structure and bonding. It describes the structure of atoms including protons, neutrons, and electrons. It explains how atomic number determines the element and how isotopes have the same number of protons but different neutrons. Electron configuration and quantum numbers are also summarized. The three main types of bonds - ionic, covalent, and metallic - are introduced along with how they influence material properties.
The document discusses several topics related to atomic structure and quantum mechanics. It begins by discussing quantization and how the work of Planck, Einstein, and others led to the concept of photons and quantized energy levels in atoms. It then discusses the photoelectric effect demonstrated by Einstein that helped establish the particle nature of light. Finally, it discusses population inversion in lasers and how certain materials like argon can be excited to a state that allows for stimulated emission of coherent light.
This document provides an overview of key concepts in nuclear physics covered in Chapter 43, including:
1) Properties of nuclei such as nucleon number, radius, density, isotopes, and nuclear magnetic moments.
2) Nuclear models including the liquid drop model and shell model to describe nuclear stability.
3) Nuclear binding energy and how it depends on proton and neutron numbers. The nucleus with the highest binding energy per nucleon is 62Ni.
4) Radioactivity and different types of nuclear decay processes, including alpha decay, beta decay, and gamma decay. Stable nuclides lie along an asymmetric line in the nuclear chart that favors more neutrons than protons for higher atomic masses.
1. The document discusses the early development of theories of light and quanta, including Planck's theory that energy can only be emitted or absorbed in discrete quanta and Einstein's proposal that light has particle-like properties as photons.
2. It explains how Bohr used Planck and Einstein's work to develop his quantum model of the hydrogen atom, which successfully explained the atomic emission spectrum of hydrogen.
3. De Broglie later proposed that all particles have both particle-like and wave-like properties, which provided an explanation for the fixed, quantized energy levels in Bohr's model of the hydrogen atom.
This document provides an overview of the principles of laser operation. It discusses:
- Laser cavities consisting of an amplifying medium between two mirrors that provide feedback.
- Fabry-Perot resonators and the standing wave patterns that form from interference between waves moving in opposite directions within the cavity.
- Population inversion being necessary for stimulated emission to exceed absorption, allowing amplification of light passing through the active medium.
- Optical pumping being used to invert the population by exciting atoms to a long-lived excited state, building up a population there.
- Stimulated emission causing photons to be emitted in phase with the stimulating photon, allowing amplification through an avalanche effect within the inverted medium.
The document summarizes key topics in the chapter on nuclear physics, including:
1) The structure and properties of the nucleus, including its composition of protons and neutrons.
2) The discovery of the neutron by James Chadwick in 1932, which helped explain nuclear structure.
3) The strong and weak nuclear forces that bind nucleons together in the nucleus.
Classical mechanics fails to explain several experimental observations such as:
1) Black-body radiation spectrum
2) Photoelectric effect
3) Compton scattering
4) Spectrum of hydrogen emissions
Quantum mechanics was developed to account for these phenomena by treating electrons as both particles and waves. Max Planck proposed quanta to explain black-body radiation, while Albert Einstein and Niels Bohr used quanta to explain the photoelectric effect and hydrogen spectrum respectively. Arthur Compton also explained Compton scattering using photons colliding with electrons.
This document provides an overview of radiation and ionizing radiation. It defines radiation as energy in the form of electromagnetic waves or particulate matter that travels through the air. It describes the basic particles that make up atoms - protons, neutrons, and electrons - and how atoms are composed. Unstable atoms emit radiation as they seek stability. There are various types of ionizing radiation, including alpha particles, beta particles, gamma rays, x-rays, and neutrons. Radiation exposure and dose are quantified, and biological effects of radiation at both the cellular level and for the human body are discussed. Controls for radiation include time, distance, and shielding to reduce exposure. Monitoring programs are also outlined.
The document summarizes Rutherford's alpha scattering experiment and its implications. It showed that atoms have small, dense nuclei containing their mass, surrounded by empty space. This contradicted the plum pudding model of atoms as diffuse positive charges. Later, Bohr proposed his model of electrons orbiting in discrete energy levels, explaining atomic spectra. However, it did not fully resolve issues like why electrons don't collapse into the nucleus.
Planck's Quantum Theory and Discovery of X-raysSidra Javed
Planck's quantum theory
Discovery of X-rays and explanation of production of X-rays, relation between atomic number and frequency of X-rays, application and uses of X-rays.
1. The document discusses the electronic structure of atoms, including the wave-particle duality of electrons.
2. It describes how electrons can only occupy certain quantized energy levels around the nucleus, and how electrons moving between these levels explains atomic emission spectra.
3. The key ideas of Planck, Bohr, de Broglie, and Heisenberg helped develop our modern understanding of electrons as behaving as both particles and waves simultaneously in atoms.
Nuclear physics involves different types of radioactive decays such as alpha decay where a nucleus loses two protons and two neutrons decreasing its atomic number by two and mass number by four, gamma decay where a nucleus in an excited state decays to a lower energy state by emitting a gamma ray photon without changing atomic or mass numbers, and decay series where a parent nucleus decays into one or more daughter nuclei through successive decays. Radioactive decay rates depend on factors like the strong and electromagnetic forces, and radioactive decay inside Earth from elements like uranium and thorium produces heat through high-energy particles, providing an internal heat source that has kept Earth's interior hotter than
This document discusses the wave-particle duality of light and matter. It explains how experiments demonstrating the photoelectric effect and electron diffraction show that electromagnetic radiation and electrons exhibit both wave-like and particle-like properties depending on the situation. De Broglie hypothesized that all particles can behave as waves, and he formulated an equation showing that particles are associated with a wavelength determined by their momentum and Planck's constant.
Atomic emission spectra and the quantum mechanical model Angbii Gayden
1) Atomic emission spectra provide evidence that electrons within atoms can only occupy discrete energy levels. When electrons drop from higher to lower energy levels, they emit photons of light at specific wavelengths, producing lines in the atomic emission spectrum.
2) Max Planck proposed that electromagnetic radiation like light is emitted and absorbed in discrete quanta of energy called photons, where the energy of each photon is directly proportional to its frequency.
3) Albert Einstein applied Planck's quantum theory to explain the photoelectric effect, proposing that light behaves as a particle as well as a wave, with a quantum of energy depending on its frequency.
Photoelectric Effect And Dual Nature Of Matter And Radiation Class 12Self-employed
This document discusses the photoelectric effect and the dual wave-particle nature of matter and light. It covers:
1) An overview of the photoelectric effect and how it demonstrated the particle nature of light via Einstein's photoelectric equation.
2) De Broglie's hypothesis that matter has wave-like properties described by the de Broglie wavelength.
3) Daviesson and Germer's experiment demonstrating the wave-like diffraction of electrons from a crystal lattice, verifying matter waves.
This document provides an overview of spectroscopy and how it can be used to determine the composition of astronomical objects. It discusses how light interacts with matter on an atomic level, causing absorption and emission spectra that act as "elemental barcodes." The spectra are caused by electrons transitioning between quantized energy levels in atoms and emitting or absorbing photons of specific wavelengths. Measuring the absorption lines in a star's spectrum allows astronomers to identify the elements present in a star's atmosphere and determine its chemical composition, such as the fact that hydrogen and helium make up over 97% of the Sun's mass.
Light interacts with materials through reflection, absorption, transmission, and refraction. When light passes from one medium to another, its speed changes, causing refraction. Reflection occurs at interfaces and depends on the refractive indices. Absorption is determined by electron transitions and occurs only for photon energies exceeding the band gap. Materials are classified as transparent, translucent, or opaque based on their transmission properties. The color of materials arises from wavelengths of light that are transmitted or re-emitted after absorption. Optical fibers use total internal reflection to transmit light signals over long distances.
Bohr's model of the atom proposed that electrons orbit the nucleus in fixed orbits and absorb or emit discrete amounts of energy when changing orbits. Later evidence showed electrons exist as a probabilistic electron cloud rather than fixed orbits. Atomic orbitals represent regions where electrons are most likely found and electrons occupy orbitals according to their electron configuration, which arranges them in the lowest energy state.
Electrons in Atoms can be summarized as follows:
1) Light exhibits both wave-like and particle-like properties, with electrons in atoms also displaying wave-like characteristics that help explain atomic structure.
2) Atoms are arranged according to a set of rules, with electrons occupying specific energy levels and orbitals around the nucleus according to the aufbau principle and other quantum rules.
3) The Bohr and quantum mechanical models both describe the discrete energy levels electrons can occupy in atoms, with the latter treating electrons as waves rather than fixed orbits and establishing probability distributions rather than precise paths.
Electrons are important because their arrangement in atomic orbitals determines an element's properties and reactions. Electrons exhibit both wave-like and particle-like behavior. According to quantum theory, electrons occupy specific atomic orbitals and energy levels. Their configuration is defined by rules like the Aufbau principle and Pauli exclusion principle. Valence electrons in the outermost shell determine an element's chemical behavior.
This document discusses the electronic structure of atoms. It begins by reviewing early atomic models proposed by Thomson, Rutherford, and Chadwick that included a dense nucleus surrounded by electrons. The document then discusses how quantum mechanics provides a better model of electronic structure through the use of orbitals and quantum numbers to describe allowed electron configurations. Key points covered include the wave-particle duality of electrons, Schrodinger's wave equation describing orbital shape and orientation, and the four quantum numbers (n, l, ml, ms) that provide unique descriptions of electron states.
1. The document provides an overview and review of topics covered on the AP Physics B exam related to modern physics, including the photoelectric effect, Bohr model of the atom, and nuclear physics.
2. It describes Einstein's explanation of the photoelectric effect involving photons and how it resolved issues not explained by classical wave theory.
3. It also explains the Bohr model of the hydrogen atom, including Bohr's assumptions and how it leads to quantized electron orbits that can explain atomic emission spectra.
The document discusses atomic structure and bonding. It describes the structure of atoms including protons, neutrons, and electrons. It explains how atomic number determines the element and how isotopes have the same number of protons but different neutrons. Electron configuration and quantum numbers are also summarized. The three main types of bonds - ionic, covalent, and metallic - are introduced along with how they influence material properties.
The document discusses several topics related to atomic structure and quantum mechanics. It begins by discussing quantization and how the work of Planck, Einstein, and others led to the concept of photons and quantized energy levels in atoms. It then discusses the photoelectric effect demonstrated by Einstein that helped establish the particle nature of light. Finally, it discusses population inversion in lasers and how certain materials like argon can be excited to a state that allows for stimulated emission of coherent light.
1) The document discusses the electronic structure of atoms, including the quantum mechanical model of the atom and how it explains experimental observations.
2) Key aspects covered include the wave-particle duality of electrons and light, the development of quantum numbers to describe electron orbitals and energies, and how the organization of electrons in atoms is reflected in the periodic table.
3) The document also notes some anomalies that arise when s and d orbitals are partially filled due to their similar energies.
Diploma sem 2 applied science physics-unit 5-chap-2 photoelectric effectRai University
This document summarizes the photoelectric effect and its laws and characteristics. It describes how the photoelectric effect was discovered and involves the emission of electrons from metal surfaces when light shines on it. The key laws are that photoelectric current is proportional to light intensity, there is a threshold frequency below which no emission occurs, and kinetic energy depends on frequency not intensity. Characteristics explained include how intensity affects current but not energy, and how increasing frequency increases energy. Einstein's model using photons is described along with the photoelectric equation. Applications of photocells are provided.
1) The document discusses the interaction of radiation with matter, including the different types of radiation and their properties. It describes electromagnetic radiation and the electromagnetic spectrum.
2) The main interactions that occur between radiation and matter are photoelectric effect, Compton scattering, and pair production. The photoelectric effect involves the ejection of an electron from an atom when a photon transfers all its energy. Compton scattering is the scattering of photons by loosely bound electrons, resulting in energy transfer. Pair production occurs when a photon converts into an electron-positron pair in the vicinity of a nucleus.
3) The dominant interaction depends on the photon energy - photoelectric effect dominates at low energies, Compton scattering in the soft
This document discusses the structure of the atom. It begins by describing Bohr's model of the atom and its limitations. It then introduces shells and subshells, as well as quantum numbers and the shapes of atomic orbitals. Rules for filling electrons into orbitals, such as the Aufbau principle and Pauli exclusion principle, are also covered. The document discusses atomic spectra, photoelectric effect, and the dual wave-particle nature of light and matter. It provides an overview of concepts like de Broglie wavelength, Heisenberg uncertainty principle, and atomic electron configuration.
This document discusses Rutherford's atomic model and Bohr's model of the atom. It provides details of Rutherford's alpha particle scattering experiment which showed that atoms have a small, dense nucleus. This led Rutherford to propose a planetary model of the atom with electrons orbiting the nucleus. The document then discusses limitations of Rutherford's model and how Bohr proposed quantized electron orbits to explain atomic stability. It provides Bohr's key postulates and formulas for the hydrogen atom spectrum and energy levels.
This document discusses the electromagnetic spectrum and properties of light. It describes how light exhibits both wave-like and particle-like properties. The wave properties of light include frequency, wavelength, speed and amplitude. The particle properties include photons and the photoelectric effect. The document also covers the Bohr model of the hydrogen atom and how it led to the development of quantum theory, which explained atomic spectra and the dual wave-particle nature of matter and energy.
This chapter discusses the nature of light and its properties. It covers topics such as:
- Light behaving as both a particle and a wave
- Blackbody radiation and the relationship between an object's temperature and emitted radiation
- Photons and Planck's law relating photon energy to frequency and wavelength
- Atomic structure and emission spectra, including Kirchhoff's laws of spectral analysis
- The Doppler effect and how an object's motion affects the observed wavelength of its emitted light.
Summary of Flame Testing and the Bohr Model - Revised.pptNicoPleta1
Niels Bohr proposed his quantum model of the atom in 1913, which explained atomic emission spectra. His model showed that electrons exist in discrete energy levels and can only absorb and emit electromagnetic radiation in specific quantized amounts as they transition between these levels. When electrons absorb energy and move to a higher level, they emit a photon of specific wavelength when dropping back down, appearing as spectral lines. Bohr's model successfully explained the hydrogen spectrum but had limitations and was later improved upon.
INTERACTION OF IONIZING RADIATION WITH MATTERVinay Desai
The document discusses the interaction of ionizing radiation with matter. It describes the main interaction processes including photoelectric effect, Compton scattering, and pair production. For radiation therapy, Compton scattering is the most important interaction as it allows high energy beams to penetrate tissue more uniformly depositing dose. The photoelectric effect is more significant for diagnostic radiology due to its dependence on atomic number.
X-rays are produced when high-energy electrons collide with a metal target in an x-ray tube. Electrons are emitted from a heated cathode and accelerated toward the anode by a high voltage potential. Some electrons interact with atoms in the anode, producing x-ray photons. X-rays have different energies depending on the target material and voltage used. Additional filtration is often applied to produce clinically useful x-ray beams. Exposure factors like voltage, current, and time determine the quantity and quality of the emitted x-rays. X-rays are used to generate medical images by exploiting their ability to pass through and be absorbed by different tissues.
The document provides an overview of atomic structure and the periodic table. It discusses how atoms are mostly empty space and their origins in stars. Atoms are made up of protons, neutrons, and electrons. Isotopes have the same number of protons but different neutrons. The periodic table organizes the elements based on their atomic structure. Electrons can only occupy certain energy levels, explaining the emission of light in distinct frequencies.
1) The document discusses the structure of atoms and nuclei. It summarizes several historic atomic models including Thomson's plum pudding model, Rutherford's nuclear model, and Bohr's early quantum model of the hydrogen atom.
2) Key aspects of atomic nuclei are described, including their composition of protons and neutrons. The properties of isotopes, isobars, and isotones are defined.
3) Nuclear forces, binding energy, and radioactive decay processes such as alpha decay and beta decay are explained. Alpha decay results in the emission of an alpha particle (helium nucleus) while beta decay changes a neutron to a proton or vice versa.
This document discusses suffixes and terminology used in medicine. It begins by listing common combining forms used to build medical terms and their meanings. It then defines several noun, adjective, and shorter suffixes and provides their meanings. Examples are given of medical terms built using combining forms and suffixes. The document also examines specific medical concepts in more depth, such as hernias, blood cells, acromegaly, splenomegaly, and laparoscopy.
The document is a chapter from a medical textbook that discusses anatomical terminology pertaining to the body as a whole. It defines the structural organization of the body from cells to tissues to organs to systems. It also describes the body cavities and identifies the major organs contained within each cavity, as well as anatomical divisions of the abdomen and back.
This document is from a textbook on medical terminology. It discusses the basic structure of medical words and how they are built from prefixes, suffixes, and combining forms. Some key points:
- Medical terms are made up of elements including roots, suffixes, prefixes, and combining vowels. Understanding these elements is important for analyzing terms.
- Common prefixes include hypo-, epi-, and cis-. Common suffixes include -itis, -algia, and -ectomy.
- Dozens of combining forms are provided, such as gastro- meaning stomach, cardi- meaning heart, and aden- meaning gland.
- Rules are provided for analyzing terms, such as reading from the suffix backward and dropping combining vowels before suffixes starting with vowels
This document is the copyright information for Chapter 25 on Cancer from the 6th edition of the textbook Molecular Cell Biology published in 2008 by W. H. Freeman and Company. The chapter was authored by a team that includes Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh, and Matsudaira.
This document is the copyright information for Chapter 24 on Immunology from the 6th edition of the textbook Molecular Cell Biology published in 2008 by W. H. Freeman and Company. The chapter was authored by Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh, and Matsudaira.
Nerve cells, also known as neurons, are highly specialized cells that process and transmit information through electrical and chemical signals. This chapter discusses the structure and function of neurons, how they communicate with each other via synapses, and how signals are propagated along neurons through changes in their membrane potentials. Neurons play a vital role in the nervous system by allowing organisms to process information and coordinate their responses.
This document is the copyright information for Chapter 22 from the 6th edition of the textbook "Molecular Cell Biology" published in 2008 by W. H. Freeman and Company. The chapter is titled "The Molecular Cell Biology of Development" and is authored by Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh, and Matsudaira.
This document is the copyright information for Chapter 21 from the sixth edition of the textbook "Molecular Cell Biology" published in 2008 by W. H. Freeman and Company. The chapter is titled "Cell Birth, Lineage, and Death" and is authored by Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh, and Matsudaira.
This document is the copyright page for Chapter 20 from the 6th edition of the textbook "Molecular Cell Biology" published in 2008 by W. H. Freeman and Company. The chapter is titled "Regulating the Eukaryotic Cell Cycle" and is authored by a group of scientists including Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh, and Matsudaira.
This document is the copyright information for Chapter 19 from the 6th edition textbook "Molecular Cell Biology" published in 2008 by W. H. Freeman and Company. The chapter is titled "Integrating Cells into Tissues" and is authored by Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh, and Matsudaira.
This chapter discusses microtubules and intermediate filaments, which are types of cytoskeletal filaments that help organize and move cellular components. Microtubules are involved in processes like cell division and intracellular transport, while intermediate filaments provide mechanical strength and help integrate the nucleus with the cytoplasm. Together, these filaments play important structural and functional roles in eukaryotic cells.
This chapter discusses microfilaments, which are one of the three main types of cytoskeletal filaments found in eukaryotic cells. Microfilaments are composed of actin filaments and play important roles in cell motility, structure, and intracellular transport. They allow cells to change shape and to move by contracting or extending parts of the cell surface.
This document is the copyright page for Chapter 16 from the 6th edition of the textbook "Molecular Cell Biology" published in 2008 by W. H. Freeman and Company. The chapter is titled "Signaling Pathways that Control Gene Activity" and is authored by a group of scientists including Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh and Matsudaira.
This document is the copyright page for Chapter 15 of the 6th edition textbook "Molecular Cell Biology" by Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh, and Matsudaira. It provides the chapter title "Cell Signaling I: Signal Transduction and Short-Term Cellular Responses" and notes the copyright is held by W. H. Freeman and Company in 2008.
This document is the copyright page for Chapter 14 from the 6th edition textbook "Molecular Cell Biology" published in 2008 by W. H. Freeman and Company. The chapter is titled "Vesicular Traffic, Secretion, and Endocytosis" and is authored by a group of scientists including Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh and Matsudaira.
This chapter discusses how proteins are transported into membranes and organelles within cells. Proteins destined for membranes or organelles have targeting signals that are recognized by transport systems. The transport systems then direct the proteins to their proper destinations, such as inserting membrane proteins into membranes or delivering soluble proteins into organelles.
This document is the copyright information for Chapter 12 from the sixth edition of the textbook "Molecular Cell Biology" published in 2008 by W. H. Freeman and Company. The chapter is titled "Cellular Energetics" and is authored by Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh, and Matsudaira.
This chapter discusses the transmembrane transport of ions and small molecules across cell membranes. It covers topics such as passive transport through membrane channels and pumps, as well as active transport using ATP. The chapter is from the 6th edition of the textbook Molecular Cell Biology and is copyrighted by W. H. Freeman and Company in 2008.
This document is the copyright information for Chapter 10, titled "Biomembrane Structure", from the sixth edition of the textbook "Molecular Cell Biology" published in 2008 by W. H. Freeman and Company. The chapter was written by a team of authors including Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh and Matsudaira.
This document is the copyright information for Chapter 9 from the 6th edition of the textbook "Molecular Cell Biology" published in 2008 by W. H. Freeman and Company. The chapter is titled "Visualizing, Fractionating, and Culturing Cells" and is authored by Lodish, Berk, Kaiser, Krieger, Scott, Bretscher, Ploegh, and Matsudaira.
LAND USE LAND COVER AND NDVI OF MIRZAPUR DISTRICT, UPRAHUL
This Dissertation explores the particular circumstances of Mirzapur, a region located in the
core of India. Mirzapur, with its varied terrains and abundant biodiversity, offers an optimal
environment for investigating the changes in vegetation cover dynamics. Our study utilizes
advanced technologies such as GIS (Geographic Information Systems) and Remote sensing to
analyze the transformations that have taken place over the course of a decade.
The complex relationship between human activities and the environment has been the focus
of extensive research and worry. As the global community grapples with swift urbanization,
population expansion, and economic progress, the effects on natural ecosystems are becoming
more evident. A crucial element of this impact is the alteration of vegetation cover, which plays a
significant role in maintaining the ecological equilibrium of our planet.Land serves as the foundation for all human activities and provides the necessary materials for
these activities. As the most crucial natural resource, its utilization by humans results in different
'Land uses,' which are determined by both human activities and the physical characteristics of the
land.
The utilization of land is impacted by human needs and environmental factors. In countries
like India, rapid population growth and the emphasis on extensive resource exploitation can lead
to significant land degradation, adversely affecting the region's land cover.
Therefore, human intervention has significantly influenced land use patterns over many
centuries, evolving its structure over time and space. In the present era, these changes have
accelerated due to factors such as agriculture and urbanization. Information regarding land use and
cover is essential for various planning and management tasks related to the Earth's surface,
providing crucial environmental data for scientific, resource management, policy purposes, and
diverse human activities.
Accurate understanding of land use and cover is imperative for the development planning
of any area. Consequently, a wide range of professionals, including earth system scientists, land
and water managers, and urban planners, are interested in obtaining data on land use and cover
changes, conversion trends, and other related patterns. The spatial dimensions of land use and
cover support policymakers and scientists in making well-informed decisions, as alterations in
these patterns indicate shifts in economic and social conditions. Monitoring such changes with the
help of Advanced technologies like Remote Sensing and Geographic Information Systems is
crucial for coordinated efforts across different administrative levels. Advanced technologies like
Remote Sensing and Geographic Information Systems
9
Changes in vegetation cover refer to variations in the distribution, composition, and overall
structure of plant communities across different temporal and spatial scales. These changes can
occur natural.
This document provides an overview of wound healing, its functions, stages, mechanisms, factors affecting it, and complications.
A wound is a break in the integrity of the skin or tissues, which may be associated with disruption of the structure and function.
Healing is the body’s response to injury in an attempt to restore normal structure and functions.
Healing can occur in two ways: Regeneration and Repair
There are 4 phases of wound healing: hemostasis, inflammation, proliferation, and remodeling. This document also describes the mechanism of wound healing. Factors that affect healing include infection, uncontrolled diabetes, poor nutrition, age, anemia, the presence of foreign bodies, etc.
Complications of wound healing like infection, hyperpigmentation of scar, contractures, and keloid formation.
Communicating effectively and consistently with students can help them feel at ease during their learning experience and provide the instructor with a communication trail to track the course's progress. This workshop will take you through constructing an engaging course container to facilitate effective communication.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
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Answers about how you can do more with Walmart!"
Chapter wise All Notes of First year Basic Civil Engineering.pptxDenish Jangid
Chapter wise All Notes of First year Basic Civil Engineering
Syllabus
Chapter-1
Introduction to objective, scope and outcome the subject
Chapter 2
Introduction: Scope and Specialization of Civil Engineering, Role of civil Engineer in Society, Impact of infrastructural development on economy of country.
Chapter 3
Surveying: Object Principles & Types of Surveying; Site Plans, Plans & Maps; Scales & Unit of different Measurements.
Linear Measurements: Instruments used. Linear Measurement by Tape, Ranging out Survey Lines and overcoming Obstructions; Measurements on sloping ground; Tape corrections, conventional symbols. Angular Measurements: Instruments used; Introduction to Compass Surveying, Bearings and Longitude & Latitude of a Line, Introduction to total station.
Levelling: Instrument used Object of levelling, Methods of levelling in brief, and Contour maps.
Chapter 4
Buildings: Selection of site for Buildings, Layout of Building Plan, Types of buildings, Plinth area, carpet area, floor space index, Introduction to building byelaws, concept of sun light & ventilation. Components of Buildings & their functions, Basic concept of R.C.C., Introduction to types of foundation
Chapter 5
Transportation: Introduction to Transportation Engineering; Traffic and Road Safety: Types and Characteristics of Various Modes of Transportation; Various Road Traffic Signs, Causes of Accidents and Road Safety Measures.
Chapter 6
Environmental Engineering: Environmental Pollution, Environmental Acts and Regulations, Functional Concepts of Ecology, Basics of Species, Biodiversity, Ecosystem, Hydrological Cycle; Chemical Cycles: Carbon, Nitrogen & Phosphorus; Energy Flow in Ecosystems.
Water Pollution: Water Quality standards, Introduction to Treatment & Disposal of Waste Water. Reuse and Saving of Water, Rain Water Harvesting. Solid Waste Management: Classification of Solid Waste, Collection, Transportation and Disposal of Solid. Recycling of Solid Waste: Energy Recovery, Sanitary Landfill, On-Site Sanitation. Air & Noise Pollution: Primary and Secondary air pollutants, Harmful effects of Air Pollution, Control of Air Pollution. . Noise Pollution Harmful Effects of noise pollution, control of noise pollution, Global warming & Climate Change, Ozone depletion, Greenhouse effect
Text Books:
1. Palancharmy, Basic Civil Engineering, McGraw Hill publishers.
2. Satheesh Gopi, Basic Civil Engineering, Pearson Publishers.
3. Ketki Rangwala Dalal, Essentials of Civil Engineering, Charotar Publishing House.
4. BCP, Surveying volume 1
Gender and Mental Health - Counselling and Family Therapy Applications and In...PsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
Philippine Edukasyong Pantahanan at Pangkabuhayan (EPP) CurriculumMJDuyan
(𝐓𝐋𝐄 𝟏𝟎𝟎) (𝐋𝐞𝐬𝐬𝐨𝐧 𝟏)-𝐏𝐫𝐞𝐥𝐢𝐦𝐬
𝐃𝐢𝐬𝐜𝐮𝐬𝐬 𝐭𝐡𝐞 𝐄𝐏𝐏 𝐂𝐮𝐫𝐫𝐢𝐜𝐮𝐥𝐮𝐦 𝐢𝐧 𝐭𝐡𝐞 𝐏𝐡𝐢𝐥𝐢𝐩𝐩𝐢𝐧𝐞𝐬:
- Understand the goals and objectives of the Edukasyong Pantahanan at Pangkabuhayan (EPP) curriculum, recognizing its importance in fostering practical life skills and values among students. Students will also be able to identify the key components and subjects covered, such as agriculture, home economics, industrial arts, and information and communication technology.
𝐄𝐱𝐩𝐥𝐚𝐢𝐧 𝐭𝐡𝐞 𝐍𝐚𝐭𝐮𝐫𝐞 𝐚𝐧𝐝 𝐒𝐜𝐨𝐩𝐞 𝐨𝐟 𝐚𝐧 𝐄𝐧𝐭𝐫𝐞𝐩𝐫𝐞𝐧𝐞𝐮𝐫:
-Define entrepreneurship, distinguishing it from general business activities by emphasizing its focus on innovation, risk-taking, and value creation. Students will describe the characteristics and traits of successful entrepreneurs, including their roles and responsibilities, and discuss the broader economic and social impacts of entrepreneurial activities on both local and global scales.
Main Java[All of the Base Concepts}.docxadhitya5119
This is part 1 of my Java Learning Journey. This Contains Custom methods, classes, constructors, packages, multithreading , try- catch block, finally block and more.
Temple of Asclepius in Thrace. Excavation resultsKrassimira Luka
The temple and the sanctuary around were dedicated to Asklepios Zmidrenus. This name has been known since 1875 when an inscription dedicated to him was discovered in Rome. The inscription is dated in 227 AD and was left by soldiers originating from the city of Philippopolis (modern Plovdiv).
Liberal Approach to the Study of Indian Politics.pdf
Chapter06 130905234714-
1. Larry Brown
Tom Holme
Jacqueline Bennett • SUNY Oneonta
www.cengage.com/chemistry/brown
Chapter 6
The Periodic Table
and Atomic Structure
2. 2
Chapter Objectives
• Describe similarities and differences between various light
sources.
• Describe waves in terms of frequency, wavelength, and
amplitude.
• Interconvert between the frequency, wavelength, and
amplitude of light and relate those those quantities to
characteristics such as color and brightness.
• Describe the photoelectric effect by stating what sort of
experiment is involved and what results are seen.
3. 3
Chapter Objectives
• Explain how the results of the photoelectric effect experiment
are consistent with a photon model of light.
• Use Planck’s equation to calculate the energy of a photon
from its wavelength or frequency.
• Use ideas about conservation of energy to explain how the
observation of atomic spectra implies that atoms have
quantized energies.
4. 4
Chapter Objectives
• Use an energy-level diagram to predict the wavelengths or
frequencies of light that an atom will absorb or emit, or use
the observed wavelengths or frequencies to determine the
allowed energy levels.
• Describe similarities and differences between the Bohr model
and the quantum mechanical model of atomic structure.
• Recognize how quantum numbers arise as a consequence of
the wave model.
• Define the term orbital.
5. 5
Chapter Objectives
• Identify an orbital (as 1s, 3p, etc.) from its quantum numbers
or vice versa.
• List the number of orbitals of each type (1s, 3p, etc.) in an
atom.
• Sketch the shapes of s and p orbitals and recognize orbitals
by their shapes.
• Rank various orbitals in terms of size and energy.
6. 6
Chapter Objectives
• Use the Pauli exclusion principle and Hund’s rule to write
electron configurations for atoms and ions of main group
elements.
• Explain the connection between valence electron
configurations and the periodic table.
• Define the following properties of atoms: atomic radius,
ionization energy, and electron affinity.
• State how the above properties vary with position in the
periodic table.
7. 7
Incandescent and Fluorescent Lights
• When metals are heated, they glow (incandescence)
• The specific color of light emitted depends on the
temperature of the metal.
• Low temperature emission is red, higher temperature
emission is orange, and eventually the emission becomes
white.
• Light bulbs produce light by heating a metal filament with
electricity.
8. 8
Incandescent and Fluorescent Lights
• Tungsten metal glows white
when electrical current
passes through the filament.
• Filament temperature is
about 4000o
F.
9. 9
Incandescent and Fluorescent Lights
• Gases can be made to emit light when an arc of electricity
passes through a poorly conducting gas.
• The electrical arc excites gas molecules, which emit light
that then interacts with the phosphor to reemit light of
many different possible colors. (fluorescence)
10. 10
The Electromagnetic Spectrum
• Visible light is a small portion of
the electromagnetic radiation
spectrum detected by our eyes.
• Electromagnetic radiation includes
radio waves, microwaves and X-
rays.
• Described as a wave traveling
through space.
• There are two components to
electromagnetic radiation, an
electric field and magnetic field.
11. 11
The Wave Nature of Light
• Wavelength, λ, is the distance
between two corresponding
points on a wave.
• Amplitude is the size or
“height” of a wave.
• Frequency, ν, is the number of
cycles of the wave passing a
given point per second, usually
expressed in Hz.
12. 12
The Wave Nature of Light
• The fourth variable of light is velocity.
• All light has the same speed in a vacuum.
• c = 2.99792458 x 108
m/s
• The product of the frequency and wavelength is the speed
of light.
• Frequency is inversely proportional to wavelength.
c = λν
13. 13
The Wave Nature of Light
• Refraction is the bending of light when it passes from one
medium to another of different density.
• Speed of light changes.
• Light bends at an angle depending on its wavelength.
• Light separates into its component colors.
14. 14
The Wave Nature of Light
• Electromagnetic radiation can be categorized in terms of
wavelength or frequency.
• Visible light is a small portion of the entire electromagnetic
spectrum.
15. 15
Example Problem 6.1
• Neon lights emit an orange-red colored glow. This light has a
wavelength of 670 nm. What is the frequency of this light?
16. 16
The Particulate Nature of Light
• Photoelectric effect: light striking a metal surface generates
photoelectrons.
• The light’s energy is transferred to electrons in metal.
• With sufficient energy, electrons “break free” of the metal.
• Electrons given more energy move faster (have higher
kinetic energy) when they leave the metal.
17. 17
The Particulate Nature of Light
• Photoelectric effect is used
in photocathodes.
• Light strikes the cathode
at frequency ν. Electrons
are ejected if ν exceeds
the threshold value ν0.
• Electrons are collected
at the anode.
• Current flow is used to
monitor light intensity.
18. 18
Photoelectric Experiments
a) For ν> ν0, the number of electrons
emitted is independent of frequency.
Value of ν0 depends on metal used.
b) As light intensity increases, the
number of photoelectrons increases.
c) As frequency increases, kinetic
energy of emitted electrons increases
linearly.
d) The kinetic energy of emitted
electrons is independent of light
intensity.
19. 19
The Particulate Nature of Light
• The photoelectric effect is not explained using a wave description
but is explained by modeling light as a particle.
• Wave-particle duality - depending on the situation, light is best
described as a wave or a particle.
• Light is best described as a particle when light is imparting
energy to another object.
• Particles of light are called photons.
• Neither waves nor particles provide an accurate description of
all the properties of light. Use the model that best describes the
properties being examined.
20. 20
The Particulate Nature of Light
• The energy of a photon (E) is proportional to the frequency
(ν).
• and is inversely proportional to the wavelength (λ).
• h = Planck’s constant = 6.626 x 10-34
J s
E = hν =
hc
λ
21. 21
Example Problem 6.2
• The laser in a standard laser printer emits light with a
wavelength of 780.0 nm. What is the energy of a photon of
this light?
22. 22
The Particulate Nature of Light
• Binding Energy - energy holding an electron to a metal.
• Threshold frequency, νo - minimum frequency of light
needed to emit an electron.
• For frequencies below the threshold frequency, no
electrons are emitted.
• For frequencies above the threshold frequency, extra
energy is imparted to the electrons as kinetic energy.
• Ephoton = Binding E + Kinetic E
• This explains the photoelectric effect.
23. 23
Example Problem 6.3
• In a photoelectric experiment, ultraviolet light with a
wavelength of 337 nm was directed at the surface of a piece
of potassium metal. The kinetic energy of the ejected
electrons was measured as 2.30 x 10-19
J. What is the electron
binding energy for potassium?
24. 24
Atomic Spectra
• Atomic Spectra: the particular pattern of wavelengths
absorbed and emitted by an element.
• Wavelengths are well separated or discrete.
• Wavelengths vary from one element to the next.
• Atoms can only exist in a few states with very specific
energies.
• When light is emitted, the atom goes from a higher energy
state to a lower energy state.
26. 26
Example Problem 6.4
• When a hydrogen atom undergoes a transition from E3 to E1, it
emits a photon with λ = 102.6 nm. Similarly, if the atom
undergoes a transition from E3 to E2, it emits a photon with λ =
656.3 nm. Find the wavelength of light emitted by an atom
making a transition from E2 to E1.
27. 27
The Bohr Atom
• Bohr model - electrons orbit the
nucleus in stable orbits.
Although not a completely
accurate model, it can be used
to explain absorption and
emission.
• Electrons move from low
energy to higher energy
orbits by absorbing energy.
• Electrons move from high
energy to lower energy
orbits by emitting energy.
• Lower energy orbits are
closer to the nucleus due to
electrostatics.
28. 28
The Bohr Atom
• Excited state: grouping of electrons that is not at the lowest
possible energy state.
• Ground state: grouping of electrons that is at the lowest
possible energy state.
• Atoms return to the ground state by emitting energy as
light.
29. 29
The Quantum Mechanical Model of the Atom
• Quantum mechanical model replaced the Bohr model of the
atom.
• Bohr model depicted electrons as particles in circular
orbits of fixed radius.
• Quantum mechanical model depicts electrons as waves
spread through a region of space (delocalized) called an
orbital.
• The energy of the orbitals is quantized like the Bohr
model.
30. 30
The Quantum Mechanical Model of the Atom
• Diffraction of electrons shown in 1927.
• Electrons exhibit wave-like behavior.
• Wave behavior described using a wave function, the
Schrödinger equation.
• H is an operator, E is energy and ψ is the wave function.
Hψ = Eψ
31. 31
Potential Energy and Orbitals
• Total energy for electrons includes potential and kinetic
energies.
• Potential energy more important in describing atomic
structure; associated with coulombic attraction between
positive nucleus and negative electrons.
• Multiple solutions exist for the wave function for any given
potential interaction.
• n is the index that labels the different solutions.
Hψn = Eψn
32. 32
Potential Energy and Orbitals
• ψn can be written in terms of two components.
• Radial component, depends on the distance from the
nucleus.
• Angular component, depends on the direction or
orientation of electron with respect to the nucleus.
33. 33
Potential Energy and Orbitals
• The wave function may have positive and negative signs in
different regions.
• Square of the wave function, ψ2
, is always positive and
gives probability of finding an electron at any particular
point.
• Each solution of the wave function defines an orbital.
• Each solution labeled by a letter and number combination:
1s, 2s, 2p, 3s, 3p, 3d, etc.
• An orbital in quantum mechanical terms is actually a
region of space rather than a particular point.
34. 34
Quantum Numbers
• Quantum numbers - solutions to the functions used to solve
the wave equation.
• Quantum numbers used to name atomic orbitals.
• Vibrating string fixed at both ends can be used to illustrate
a function of the wave equation.
35. 35
Quantum Numbers
• A vibrating string can be
written in terms of amplitude
A, distance along the string
x, and length of the string L.
• A string fixed at both ends is
an example of how multiple
waves can satisfy a
particular set of conditions.
ψn (x)=Asin
nπx
L
36. 36
Quantum Numbers
• When solving the Schrödinger equation, three quantum
numbers are used.
• Principal quantum number, n (n = 1, 2, 3, 4, 5, …)
• Secondary quantum number, l
• Magnetic quantum number, ml
37. 37
Quantum Numbers
• The principal quantum number, n, defines the shell in which a
particular orbital is found.
• n must be a positive integer
• n = 1 is the first shell, n = 2 is the second shell, etc.
• Each shell has different energies.
38. 38
Quantum Numbers
• The secondary quantum number, l, indexes energy
differences between orbitals in the same shell in an atom.
• l has integral values from 0 to n-1.
• l specifies subshell
• Each shell contains as many l values as its value of n.
39. 39
Quantum Numbers
• The energies of orbitals are specified completely using only
the n and l quantum numbers.
• In magnetic fields, some emission lines split into three,
five, or seven components.
• A third quantum number describes splitting.
40. 40
Quantum Numbers
• The third quantum number is the magnetic quantum number,
ml.
• ml has integer values.
• ml may be either positive or negative.
• ml’s absolute value must be less than or equal to l.
• For l = 1, ml = -1, 0, +1
42. 42
Example Problem 6.5
• Write all of the allowed sets of quantum numbers (n, l, and ml)
for a 3p orbital.
43. 43
Visualizing Orbitals
• Wave functions for the first five
orbitals of hydrogen.
• The wave function is written in
spherical polar coordinates with
the nucleus at the origin.
• Point in space defined by
radius r, and angles θ and ϕ.
• r determines the orbital size.
• θ and ϕ determine the orbital
shape.
44. 44
Visualizing Orbitals
• A point in space defined by
radius r, and angles θ and ϕ.
• Chemists usually think of
orbitals in terms of pictures.
• The space occupied by an
orbital is a 90% probability
of finding an electron.
• A plot of the angular part of
the wave function gives the
shape of the corresponding
orbital.
45. 45
Visualizing Orbitals
• s orbitals are spherical
• p orbitals have two lobes separated by a nodal plane.
• A nodal plane is a plane where the probability of finding an
electron is zero (here the yz plane).
• d orbitals have more complicated shapes due to the presence
of two nodal planes.
46. 46
Visualizing Orbitals
• Nodes are explained using the Uncertainty Principle.
• It is impossible to determine both the position and
momentum of an electron simultaneously and with
complete accuracy.
• An orbital depicts the probability of finding an electron.
• The radial part of the wave function describes how the
probability of finding an electron varies with distance from the
nucleus.
• Spherical nodes are generated by the radial portion of the
wave function.
49. 49
Visualizing Orbitals
• Chemistry of halogen lights
is explained by a quantum
mechanical model of the
halogens.
• Tungsten is deposited
on the filament following
reaction with a halogen.
50. 50
The Pauli Exclusion Principle and
Electron Configurations
• The spin quantum number, ms, determines the number of
electrons that can occupy an orbital.
• ms = ±1/2
• Electrons described as “spin up” or “spin down”.
• An electron is specified by a set of four quantum numbers.
51. 51
The Pauli Exclusion Principle and
Electron Configurations
• Pauli Exclusion Principle - no two electrons in an atom may
have the same set of four quantum numbers.
• Two electrons can have the same values of n, l, and ml,
but different values of ms.
• Two electrons maximum per orbital.
• Two electrons occupying the same orbital are spin paired.
52. 52
Orbital Energies and Electron Configurations
• Electrons in smaller orbitals are held more tightly and have
lower energies.
• Orbital size increases as the value of n increases.
• True for hydrogen atoms, but not entirely true for
multielectron atoms.
• As nuclear charge increases, orbital size decreases.
• Electrons interact with other electrons as well as the
positively charged nucleus.
53. 53
Orbital Energies and Electron Configurations
• For electrons in larger orbitals, the charge “felt” is a
combination of the actual nuclear charge and the offsetting
charge of electrons in lower orbitals.
• The masking of the nuclear charge is called shielding.
• Shielding results in a reduced, effective nuclear charge.
54. 54
Orbital Energies and Electron Configurations
• Effective nuclear charge
allows for understanding of the
energy differences between
orbitals.
• 2s orbital: the small local
maximum close to the
nucleus results in an
electron with a higher
effective nuclear charge.
• 2p orbital: lacks the local
minimum close to the
nucleus of the 2s orbital.
• Lower effective nuclear
charge for 2p electrons.
55. 55
Orbital Energies and Electron Configurations
• The energy ordering for atomic orbitals is 1s, 2s, 2p, 3s, 3p,
4s, 3d, 4p, 5s, 4d, 5p, 6s, 4f, 5d, 6p, 7s, 5f, 6d, and 7p.
• An orbital’s size and penetration when treated
quantitatively produces the order of filling represented.
• Electronic configurations are written in order of energy for
atomic orbitals.
56. 56
Hund’s Rule and the Aufbau Principle
• Aufbau principle - when filling orbitals, start with the lowest
energy and proceed to the next highest energy level.
• Hund’s rule - within a subshell, electrons occupy the
maximum number of orbitals possible.
• Electron configurations are sometimes depicted using boxes
to represent orbitals. This depiction shows paired and
unpaired electrons explicitly.
58. 58
Hund’s Rule and the Aufbau Principle
• A simplified depiction uses superscripts to indicate the
number of electrons in an orbital set.
• 1s2
2s2
2p2
is the electronic configuration for carbon.
• Noble gas electronic configurations are used as a shorthand
for writing electronic configurations.
• Relates electronic structure to chemical bonding.
• Electrons in outermost occupied orbitals give rise to
chemical reactivity of an element.
• [He] 2s2
2p2
is the shorthand for carbon
59. 59
Hund’s Rule and the Aufbau Principle
• The inner electrons, which lie closer to the nucleus, are
referred to as core electrons.
• Core electrons can be represented by the noble gas with
the same electronic configuration.
• The outer electrons are usually referred to as valence
electrons.
• Valence electrons are shown explicitly when a noble gas
shorthand is used to write electronic configurations.
• Valence electrons determine reactivity.
60. 60
Example Problem 6.7
• Rewrite the electron configuration for sulfur using the
shorthand notation.
61. 61
The Periodic Table and Electron Configurations
• The periodic table and the electronic configurations
predicted by quantum mechanics are related.
• The periodic table is broken into s, p, d, and f blocks.
• Elements in each block have the same subshell for the
highest electron.
• Structure of periodic table can be used to predict
electronic configurations.
62. 62
The Periodic Table and Electron Configurations
• The shape of the periodic table can be broken down into blocks
according to the type of orbital occupied by the highest energy
electron in the ground state.
• We find the element of interest in the periodic table and write
its core electrons using the shorthand notation with the
previous rare gas element. Then we determine the valence
electrons by noting where the element sits within its own period
in the table.
63. 63
Example Problem 6.8
• Use the periodic table to determine the electron configuration
of tungsten (W), which is used in the filaments of most
incandescent lights.
64. 64
Periodic Trends in Atomic Properties
• Using the understanding of orbitals and atomic structure, it is
possible to explain some periodic properties.
• Atomic size
• Ionization energy
• Electron affinity
65. 65
Atomic Size
• The shell in which the valence electrons are found affects
atomic size.
• The size of the valence orbitals increases with n, so size
must increase from top to bottom for a group.
• The strength of the interaction between the nucleus and the
valence electrons affects atomic size.
• The effective nuclear charge increases from left to right
across a period, so the interaction between the
electrons and the nucleus increases in strength.
• As interaction strength increases, valence electrons
are drawn closer to the nucleus, decreasing atomic
size.
67. 67
Example Problem 6.9
• Using only the periodic table, rank the following elements in
order of increasing size: Fe, K, Rb, S, and Se.
68. 68
Ionization Energy
• Ionization energy - the energy required to remove an electron
from a gaseous atom, forming a cation.
• Formation of X+
is the first ionization energy, X2+
would be
the second ionization energy, etc.
• Effective nuclear charge increases left to right across a
period.
• The more strongly held an electron is, the higher the
ionization energy must be.
• As valence electrons move further from the nucleus, they
become easier to remove and the first ionization energy
becomes smaller.
X(g) → X+
(g) + e−
69. 69
Ionization Energy
• Graph of the first ionization energy (in kJ/mol) vs.
atomic number for the first 38 elements.
70. 70
Ionization Energy
• From nitrogen to oxygen, there is a slight decrease in
ionization energy.
• Nitrogen has a half-filled p subshell.
• Oxygen has a pair of p electrons in one 2p orbital.
• Ionization of oxygen relieves electron-electron repulsion,
lowering its ionization energy.
• Ionization energies increase with successive ionizations for a
given element.
• Effective nuclear charge for valence electrons is larger for
the ion than the neutral atom.
• Filled subshells of electrons are difficult to break up, which is
why it is difficult to remove electrons from noble gases.
73. 73
Example Problem 6.10
• Using only the periodic table, rank the following elements in
order of increasing ionization energy: Br, F, Ga, K, and Se.
74. 74
Electron Affinity
• Electron affinity - energy required to place an electron on a
gaseous atom, forming an anion.
• Electron affinities may have positive or negative values.
• Negative values - energy released
• Positive values - energy absorbed
• Electron affinities increase (numerical value becomes more
negative) from left to right for a period and bottom to top for a
group.
• The greater (more negative) the electron affinity, the more
stable the anion will be.
X(g) + e−
→ X–
(g)
76. 76
Modern Light Sources: LEDs and Lasers
• Light Emitting Diodes (LEDs) emit monochromatic light.
• Monochromatic light - light of a single wavelength or color.
• LEDs are solid-state devices.
• Simply a piece of solid material.
• Color emitted depends on identity of solid material.
77. 77
Modern Light Sources: LEDs and Lasers
• LEDs
• Metallic leads connect to a piece of semiconductor material.
• Color emitted is determined by chemical composition of
semiconductor.
• Superior to incandescent lights in efficiency and durability.
78. 78
Modern Light Sources: LEDs and Lasers
• Lasers emit monochromatic light; color of emitted light
depends on chemical composition of laser medium.
• Lasers emit coherent light; all light waves are perfectly in
phase and go through maxima and minima together.
79. 79
Modern Light Sources: LEDs and Lasers
• Lasers - a direct result of the emergence of the quantum
mechanical model of the atom.
• An understanding of energy levels within the laser medium
is needed.
• Laser operation relies on stimulated emission, where the
electron population of higher energy level is greater than a
lower energy level.
• Emission occurs as electrons return to lower energy
states.
• “Population inversion” in lasers established by solids, liquids
or gases.
• Solid-state lasers are used in electronics.
80. 80
Modern Light Sources: LEDs and Lasers
• Bright blue light emitted by an organic light emitting diode
(OLED).
• Holds promise of an entirely new class of paper-thin flexible
color displays.