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.
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.
This document provides an introduction to nuclear physics and radioactivity. It discusses:
1) The discovery of radioactivity and the nucleus. Rutherford's scattering experiment in 1911 revealed the existence of the nucleus as the source of radioactivity.
2) The structure of the nucleus, including its composition of protons and neutrons (nucleons), atomic number, mass number, isotopes, and typical size.
3) Nuclear stability and binding energy. The strong nuclear force holds nuclei together, and nuclei with intermediate mass numbers have the highest binding energy per nucleon. Only certain combinations of protons and neutrons produce stable nuclei.
1. Atoms are the basic building blocks of matter and consist of a small, dense nucleus surrounded by electrons.
2. Rutherford's gold foil experiment in 1911 showed that the atom has a small, dense nucleus containing positively charged protons and uncharged neutrons.
3. Niels Bohr proposed his model of the atom in 1913 where electrons orbit the nucleus in fixed shells at specific energy levels, explaining atomic spectra. However, it did not explain more complex atomic structures.
1. Atoms are the basic building blocks of matter and consist of a small, dense nucleus surrounded by electrons.
2. Rutherford's gold foil experiment in 1911 showed that the atom has a small, dense nucleus containing positively charged protons and uncharged neutrons.
3. Niels Bohr proposed his model of the atom in 1913 in which electrons orbit the nucleus in fixed shells at specific energy levels, explaining atomic spectra.
1. Atoms are the basic building blocks of matter and consist of a small, dense nucleus surrounded by electrons.
2. Rutherford's gold foil experiment in 1911 showed that the atom has a small, dense nucleus containing positively charged protons and uncharged neutrons.
3. Niels Bohr proposed his model of the atom in 1913 where electrons orbit the nucleus in fixed shells at specific energy levels, explaining atomic spectra. However, it did not explain more complex atomic structures.
Applied Chemistry, atomic and molecular structure, part 1, by Shiraz mahbob PhDMaqsoodAhmadKhan5
applied chemistry lecture and slide,
Applied Chemistry, atomic and molecular structure, part 1, by Shiraz mahbob PhD, lecturer in chemistry in pakistan institute of engineering and applied sciences
This document provides an overview of key concepts in nuclear physics covered in Chapter 43 of University Physics. It discusses properties of nuclei such as nucleon number, radius, and density. It also covers nuclear binding energy, radioactive decay, and models of nuclear structure including the liquid drop model and shell model. Examples are provided to illustrate concepts like alpha decay, beta decay, gamma emission, and the calculation of half-lives. The document concludes with a discussion of natural radioactivity and decay chains.
This document provides an overview of atomic structure, bonding, and electron distribution. It begins by defining the basic subatomic particles that make up atoms. It then discusses several historical atomic models including Thomson's plum pudding model, Rutherford's nuclear model, and Bohr's early quantum model. The document introduces concepts like electron orbitals and quantum numbers. It also covers bonding theories such as ionic and covalent bonding as well as localized and delocalized bonding. Hybridization of atomic orbitals is discussed through examples like sp, sp2, and sp3 hybridization. The summary concludes with an introduction to molecular orbital theory.
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.
This document provides an introduction to nuclear physics and radioactivity. It discusses:
1) The discovery of radioactivity and the nucleus. Rutherford's scattering experiment in 1911 revealed the existence of the nucleus as the source of radioactivity.
2) The structure of the nucleus, including its composition of protons and neutrons (nucleons), atomic number, mass number, isotopes, and typical size.
3) Nuclear stability and binding energy. The strong nuclear force holds nuclei together, and nuclei with intermediate mass numbers have the highest binding energy per nucleon. Only certain combinations of protons and neutrons produce stable nuclei.
1. Atoms are the basic building blocks of matter and consist of a small, dense nucleus surrounded by electrons.
2. Rutherford's gold foil experiment in 1911 showed that the atom has a small, dense nucleus containing positively charged protons and uncharged neutrons.
3. Niels Bohr proposed his model of the atom in 1913 where electrons orbit the nucleus in fixed shells at specific energy levels, explaining atomic spectra. However, it did not explain more complex atomic structures.
1. Atoms are the basic building blocks of matter and consist of a small, dense nucleus surrounded by electrons.
2. Rutherford's gold foil experiment in 1911 showed that the atom has a small, dense nucleus containing positively charged protons and uncharged neutrons.
3. Niels Bohr proposed his model of the atom in 1913 in which electrons orbit the nucleus in fixed shells at specific energy levels, explaining atomic spectra.
1. Atoms are the basic building blocks of matter and consist of a small, dense nucleus surrounded by electrons.
2. Rutherford's gold foil experiment in 1911 showed that the atom has a small, dense nucleus containing positively charged protons and uncharged neutrons.
3. Niels Bohr proposed his model of the atom in 1913 where electrons orbit the nucleus in fixed shells at specific energy levels, explaining atomic spectra. However, it did not explain more complex atomic structures.
Applied Chemistry, atomic and molecular structure, part 1, by Shiraz mahbob PhDMaqsoodAhmadKhan5
applied chemistry lecture and slide,
Applied Chemistry, atomic and molecular structure, part 1, by Shiraz mahbob PhD, lecturer in chemistry in pakistan institute of engineering and applied sciences
This document provides an overview of key concepts in nuclear physics covered in Chapter 43 of University Physics. It discusses properties of nuclei such as nucleon number, radius, and density. It also covers nuclear binding energy, radioactive decay, and models of nuclear structure including the liquid drop model and shell model. Examples are provided to illustrate concepts like alpha decay, beta decay, gamma emission, and the calculation of half-lives. The document concludes with a discussion of natural radioactivity and decay chains.
This document provides an overview of atomic structure, bonding, and electron distribution. It begins by defining the basic subatomic particles that make up atoms. It then discusses several historical atomic models including Thomson's plum pudding model, Rutherford's nuclear model, and Bohr's early quantum model. The document introduces concepts like electron orbitals and quantum numbers. It also covers bonding theories such as ionic and covalent bonding as well as localized and delocalized bonding. Hybridization of atomic orbitals is discussed through examples like sp, sp2, and sp3 hybridization. The summary concludes with an introduction to molecular orbital theory.
This document provides an overview of atomic physics, including:
1. Models of the atom including Rutherford and Bohr models, and explanations of atomic energy levels and quantum numbers.
2. Quantum physics concepts including Planck's quantum theory, Einstein's theories of light and the photoelectric effect, and de Broglie's hypothesis of matter waves.
3. Lasers including production of laser light, properties, types, and applications.
4. Nuclear physics including structure of the nucleus, radioactive decay, nuclear stability, fission and fusion processes, and applications of nuclear technology.
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.
The document discusses the types of radiation emitted during radioactive decay. It describes alpha, beta, and neutron radiation as particulate radiation emitted from atomic nuclei. Alpha radiation consists of helium nuclei, beta radiation can be electrons or positrons, and neutron radiation emits neutrons. Electron capture and internal conversion are also discussed as alternative decay processes.
- An atom is made up of protons, neutrons, and electrons. The nucleus consists of protons and neutrons, and electrons orbit around the nucleus.
- Each element is defined by its atomic number, which is the number of protons. Isotopes are variants of an element that differ in the number of neutrons.
- Electrons can occupy different energy levels based on quantum numbers like the principal quantum number. Absorbing or releasing energy can cause electrons to change energy levels.
The Fundamentals of Chemistry is an introduction to the Periodic Table, stoichiometry, chemical states, chemical equilibria, acid & base, oxidation & reduction reactions, chemical kinetics, inorganic nomenclature, and chemical bonding.
The document discusses the atomic theory of matter and the development of atomic structure models. It describes John Dalton's atomic theory which stated that elements are composed of atoms that are unique and atoms are neither created nor destroyed in chemical reactions. The discovery of the electron by J.J. Thompson and experiments by Robert Millikan and Ernest Rutherford helped develop the modern atomic structure model of a small, dense nucleus surrounded by electrons. The document also discusses isotopes, atomic numbers, mass numbers, and how the periodic table is arranged based on atomic structure.
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.
Atomic Structure Powerpoint Presentation by Computer CareersYaman Singhania
Powerpoint Presentation on Atomic Structure by Computer Careers.What is an Atom?ATOMIC STRUCTURE,There are two ways to represent the atomic structure of n element or compound,DOT & CROSS DIAGRAMS and many more ....
This document provides information about atomic structure. It discusses the basic parts of an atom including protons, neutrons, and electrons. Early atomic models proposed by Rutherford and Bohr are described, noting their limitations in explaining experimental observations. The modern quantum mechanical model represents electrons using quantum numbers and wave functions or "fuzzy clouds" to describe atomic orbitals. Electrons occupy different energy levels and sublevels based on their quantum numbers.
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.
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.
1) Radioactivity is the spontaneous disintegration of unstable atomic nuclei through emission of particles like alpha and beta particles or gamma rays. This transforms the parent nucleus into a more stable daughter nucleus.
2) Radioactive decay can produce daughter nuclei in excited states, which then de-excite through gamma or isomeric transitions without changing the nucleus' proton or neutron number.
3) For nuclei with unstable proton-neutron ratios, radioactive decay processes like beta decay can change the nucleus' proton or neutron number to reach a more stable ratio.
The document summarizes the evolving models of the structure of the atom over time. It describes early philosophers' ideas that matter was made of indivisible particles. John Dalton proposed the first scientific model with solid spheres. J.J. Thomson's experiments discovered electrons and the plum pudding model. Rutherford discovered the nucleus in the gold foil experiment. Later, Chadwick discovered neutrons, and Bohr incorporated quantum theory with energy levels. The modern atomic model includes electrons orbiting the nucleus, which contains protons and neutrons held together by strong nuclear forces.
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.
202006151236284892NK-Bohr Model of Hydrogen Atom.pdfsasukekun12
The document summarizes the Bohr model of the hydrogen atom. It describes the key postulates of the Bohr model, including that electrons revolve in discrete orbits without radiating energy. It explains that the angular momentum of electrons in these orbits is an integral multiple of Planck's constant. The model holds that electrons can only exist in these discrete energy levels and radiate energy when jumping between levels. However, the model has limitations and fails to explain phenomena like hyperfine structure. It was later replaced by quantum mechanical models developed by Schrodinger and others.
In 1909, Rutherford performed the Gold Foil Experiment and suggested the following characteristics of the atom:
It consists of a small core, or nucleus, that contains most of the mass of the atom
This nucleus is made up of particles called protons, which have a positive charge
The protons are surrounded by negatively charged electrons, but most of the atom is actually empty space.
In 1913, Bohor proposed the Atomic Model, which suggests that electrons travel around the nucleus of an atom in orbits or definite paths.
Atom consists of a tiny nucleus.
Each orbit has fixed energy that is quantatized.
The energy is emitted or absorb only when an electron jumps from one orbit to another.
Electron can revolve in orbits of fixed angular momentum mvr.
Liquid Drop Model
The nuclei of all elements are considered to be behave like a liquid drop of incompressible liquid of very high density.
In an equilibrium state the nuclei of atoms remain spherically symmetric under the action of strong attractive nuclear forces just like the drop of a liquid which is spherical due to surface tension.
The density of a nucleus is independent of its
size just like the density of liquid which is also
independent of its size.
The protons and neutrons of the nucleus move about
within a spherical enclosure called the nuclear
potential barrier just like the movement of the
molecules of a liquid within a spherical drop of liquid.
. The binding energy per nucleon of a nucleus is constant
Binding Energy
The binding energy, BE, of a nucleus is a measure of the strong force and represents the energy required to separate the nucleus into its constituents protons and neutrons;
Greater the binding energy, the more stable the nucleus.
Volume
The volume of the nucleus is directly proportional to the total number of nucleons present in it.
Density
The density of the nucleus is nearly constant.
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.
The document discusses the structure of the atom. It describes how atoms are composed of a nucleus containing protons and neutrons, surrounded by electrons. The nucleus is very small compared to the size of the atom. Electrons orbit the nucleus in specific energy levels. The distribution and number of electrons determines an element's properties. Nuclear stability depends on the ratio of protons to neutrons. Binding energy holds the nucleus together. Various subatomic particles like protons, neutrons and electrons have distinct properties like mass and charge. Nuclear forces interact within the nucleus. Particle radiation involves the emission and propagation of energy by particles with mass and momentum.
This document defines various terms associated with elements and their subatomic particles. It then summarizes Rutherford's gold foil experiment and conclusions that led to the nuclear model of the atom. The document continues by describing the key subatomic particles (protons, neutrons, electrons), electromagnetic spectrum, photoelectric effect, atomic spectra, Bohr's model of the hydrogen atom, de Broglie wavelength, Heisenberg's uncertainty principle, Schrodinger wave equation, shapes of orbitals, filling of orbitals according to Aufbau principle and Hund's rule.
BE UNIT-1 basic electronics unit one.pptxharisbs369
1. The document discusses the atomic structure of matter, which is made up of protons, electrons, and neutrons. Atoms contain protons and neutrons in their nucleus, surrounded by electrons.
2. Atoms of different elements have different atomic structures because they contain different numbers of protons and electrons. Neutral atoms have equal numbers of protons and electrons, but atoms can gain or lose electrons to become ions.
3. The document then discusses subatomic particles like protons, neutrons, and electrons in more detail, including their relative masses and charges. It also discusses isotopes and how they have the same number of protons but different numbers of neutrons.
Respiration and circulation are vital body systems. The respiratory system brings oxygen into the body and removes carbon dioxide through breathing and the circulatory system transports these gases throughout the body using the heart, blood and blood vessels. Together these systems work to provide oxygen and remove wastes to keep cells functioning properly.
20200915-XI-Physics-Unit and Measurement-1 of 4-Ppt.pptxRavindraWaykole
This document discusses physical quantities, units of measurement, and methods for measuring length, mass, and time. It covers:
- Fundamental physical quantities like length, mass, and time that other quantities can be derived from.
- The International System of Units (SI) which defines the meter, kilogram, second and other base units.
- How length is measured using techniques like parallax to determine distances to planets. Mass spectrometers and atomic clocks are used for small masses and time intervals.
- Various standard units used to measure length from the femtometer to the parsec, and mass units like the unified atomic mass unit. Time is kept using atomic clocks referenced to the vibration of ces
This document provides an overview of atomic physics, including:
1. Models of the atom including Rutherford and Bohr models, and explanations of atomic energy levels and quantum numbers.
2. Quantum physics concepts including Planck's quantum theory, Einstein's theories of light and the photoelectric effect, and de Broglie's hypothesis of matter waves.
3. Lasers including production of laser light, properties, types, and applications.
4. Nuclear physics including structure of the nucleus, radioactive decay, nuclear stability, fission and fusion processes, and applications of nuclear technology.
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.
The document discusses the types of radiation emitted during radioactive decay. It describes alpha, beta, and neutron radiation as particulate radiation emitted from atomic nuclei. Alpha radiation consists of helium nuclei, beta radiation can be electrons or positrons, and neutron radiation emits neutrons. Electron capture and internal conversion are also discussed as alternative decay processes.
- An atom is made up of protons, neutrons, and electrons. The nucleus consists of protons and neutrons, and electrons orbit around the nucleus.
- Each element is defined by its atomic number, which is the number of protons. Isotopes are variants of an element that differ in the number of neutrons.
- Electrons can occupy different energy levels based on quantum numbers like the principal quantum number. Absorbing or releasing energy can cause electrons to change energy levels.
The Fundamentals of Chemistry is an introduction to the Periodic Table, stoichiometry, chemical states, chemical equilibria, acid & base, oxidation & reduction reactions, chemical kinetics, inorganic nomenclature, and chemical bonding.
The document discusses the atomic theory of matter and the development of atomic structure models. It describes John Dalton's atomic theory which stated that elements are composed of atoms that are unique and atoms are neither created nor destroyed in chemical reactions. The discovery of the electron by J.J. Thompson and experiments by Robert Millikan and Ernest Rutherford helped develop the modern atomic structure model of a small, dense nucleus surrounded by electrons. The document also discusses isotopes, atomic numbers, mass numbers, and how the periodic table is arranged based on atomic structure.
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.
Atomic Structure Powerpoint Presentation by Computer CareersYaman Singhania
Powerpoint Presentation on Atomic Structure by Computer Careers.What is an Atom?ATOMIC STRUCTURE,There are two ways to represent the atomic structure of n element or compound,DOT & CROSS DIAGRAMS and many more ....
This document provides information about atomic structure. It discusses the basic parts of an atom including protons, neutrons, and electrons. Early atomic models proposed by Rutherford and Bohr are described, noting their limitations in explaining experimental observations. The modern quantum mechanical model represents electrons using quantum numbers and wave functions or "fuzzy clouds" to describe atomic orbitals. Electrons occupy different energy levels and sublevels based on their quantum numbers.
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.
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.
1) Radioactivity is the spontaneous disintegration of unstable atomic nuclei through emission of particles like alpha and beta particles or gamma rays. This transforms the parent nucleus into a more stable daughter nucleus.
2) Radioactive decay can produce daughter nuclei in excited states, which then de-excite through gamma or isomeric transitions without changing the nucleus' proton or neutron number.
3) For nuclei with unstable proton-neutron ratios, radioactive decay processes like beta decay can change the nucleus' proton or neutron number to reach a more stable ratio.
The document summarizes the evolving models of the structure of the atom over time. It describes early philosophers' ideas that matter was made of indivisible particles. John Dalton proposed the first scientific model with solid spheres. J.J. Thomson's experiments discovered electrons and the plum pudding model. Rutherford discovered the nucleus in the gold foil experiment. Later, Chadwick discovered neutrons, and Bohr incorporated quantum theory with energy levels. The modern atomic model includes electrons orbiting the nucleus, which contains protons and neutrons held together by strong nuclear forces.
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.
202006151236284892NK-Bohr Model of Hydrogen Atom.pdfsasukekun12
The document summarizes the Bohr model of the hydrogen atom. It describes the key postulates of the Bohr model, including that electrons revolve in discrete orbits without radiating energy. It explains that the angular momentum of electrons in these orbits is an integral multiple of Planck's constant. The model holds that electrons can only exist in these discrete energy levels and radiate energy when jumping between levels. However, the model has limitations and fails to explain phenomena like hyperfine structure. It was later replaced by quantum mechanical models developed by Schrodinger and others.
In 1909, Rutherford performed the Gold Foil Experiment and suggested the following characteristics of the atom:
It consists of a small core, or nucleus, that contains most of the mass of the atom
This nucleus is made up of particles called protons, which have a positive charge
The protons are surrounded by negatively charged electrons, but most of the atom is actually empty space.
In 1913, Bohor proposed the Atomic Model, which suggests that electrons travel around the nucleus of an atom in orbits or definite paths.
Atom consists of a tiny nucleus.
Each orbit has fixed energy that is quantatized.
The energy is emitted or absorb only when an electron jumps from one orbit to another.
Electron can revolve in orbits of fixed angular momentum mvr.
Liquid Drop Model
The nuclei of all elements are considered to be behave like a liquid drop of incompressible liquid of very high density.
In an equilibrium state the nuclei of atoms remain spherically symmetric under the action of strong attractive nuclear forces just like the drop of a liquid which is spherical due to surface tension.
The density of a nucleus is independent of its
size just like the density of liquid which is also
independent of its size.
The protons and neutrons of the nucleus move about
within a spherical enclosure called the nuclear
potential barrier just like the movement of the
molecules of a liquid within a spherical drop of liquid.
. The binding energy per nucleon of a nucleus is constant
Binding Energy
The binding energy, BE, of a nucleus is a measure of the strong force and represents the energy required to separate the nucleus into its constituents protons and neutrons;
Greater the binding energy, the more stable the nucleus.
Volume
The volume of the nucleus is directly proportional to the total number of nucleons present in it.
Density
The density of the nucleus is nearly constant.
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.
The document discusses the structure of the atom. It describes how atoms are composed of a nucleus containing protons and neutrons, surrounded by electrons. The nucleus is very small compared to the size of the atom. Electrons orbit the nucleus in specific energy levels. The distribution and number of electrons determines an element's properties. Nuclear stability depends on the ratio of protons to neutrons. Binding energy holds the nucleus together. Various subatomic particles like protons, neutrons and electrons have distinct properties like mass and charge. Nuclear forces interact within the nucleus. Particle radiation involves the emission and propagation of energy by particles with mass and momentum.
This document defines various terms associated with elements and their subatomic particles. It then summarizes Rutherford's gold foil experiment and conclusions that led to the nuclear model of the atom. The document continues by describing the key subatomic particles (protons, neutrons, electrons), electromagnetic spectrum, photoelectric effect, atomic spectra, Bohr's model of the hydrogen atom, de Broglie wavelength, Heisenberg's uncertainty principle, Schrodinger wave equation, shapes of orbitals, filling of orbitals according to Aufbau principle and Hund's rule.
BE UNIT-1 basic electronics unit one.pptxharisbs369
1. The document discusses the atomic structure of matter, which is made up of protons, electrons, and neutrons. Atoms contain protons and neutrons in their nucleus, surrounded by electrons.
2. Atoms of different elements have different atomic structures because they contain different numbers of protons and electrons. Neutral atoms have equal numbers of protons and electrons, but atoms can gain or lose electrons to become ions.
3. The document then discusses subatomic particles like protons, neutrons, and electrons in more detail, including their relative masses and charges. It also discusses isotopes and how they have the same number of protons but different numbers of neutrons.
Similar to 15. Structure of atoms and nuclei.pptx (20)
Respiration and circulation are vital body systems. The respiratory system brings oxygen into the body and removes carbon dioxide through breathing and the circulatory system transports these gases throughout the body using the heart, blood and blood vessels. Together these systems work to provide oxygen and remove wastes to keep cells functioning properly.
20200915-XI-Physics-Unit and Measurement-1 of 4-Ppt.pptxRavindraWaykole
This document discusses physical quantities, units of measurement, and methods for measuring length, mass, and time. It covers:
- Fundamental physical quantities like length, mass, and time that other quantities can be derived from.
- The International System of Units (SI) which defines the meter, kilogram, second and other base units.
- How length is measured using techniques like parallax to determine distances to planets. Mass spectrometers and atomic clocks are used for small masses and time intervals.
- Various standard units used to measure length from the femtometer to the parsec, and mass units like the unified atomic mass unit. Time is kept using atomic clocks referenced to the vibration of ces
Here are the key steps to calculate the mass of Earth (M) from the given data:
1) Acceleration due to gravity on Earth's surface (g) = 9.81 m/s^2
2) Universal gravitational constant (G) = 6.67x10^-11 Nm^2/kg^2
3) Radius of Earth (R) = 6.37x10^6 m
4) Using the formula for acceleration due to gravity:
g = GM/R^2
5) Rearranging the terms:
M = gR^2/G
6) Substituting the values:
M = (9.81 m/s^2)(
Chemistry was the subject of a document dated December 9th, 2019. The document was addressed to Prof. Rajnikant Bhatt of Bhavan's College of Science and Commerce located in Andheri. The document likely concerned a chemistry-related topic but provided no other details.
Altitude of a rocket- mass vs initial speed.pptRavindraWaykole
This document compares the altitude of different rockets based on their initial mass and speed in the absence of air resistance. It shows several examples of rockets with different mass and speed values and indicates which rocket in each pair would reach a higher altitude. The key factors that determine altitude are initial speed, with higher speeds reaching greater heights, and mass, with lower masses reaching greater heights. Air resistance is noted to impact altitude by providing drag on the rockets.
This document discusses key concepts related to electricity including current, potential, electromotive force, internal resistance of cells, resistance of conductors, Ohm's law, resistivity, conductivity, and combinations of resistors. It defines current as the rate of flow of charge and describes how current, potential, resistance, and resistivity are calculated. It also explains how resistance and resistivity change with temperature and the formulas for calculating equivalent resistance when resistors are combined in series or parallel.
This document summarizes a physics lecture on rotational motion. It discusses rotational kinetic energy, moment of inertia, torque, and Newton's second law for rotational motion. Key concepts covered include:
- Rotational kinetic energy depends on the moment of inertia and angular speed.
- Moment of inertia depends on the mass and how it is distributed relative to the axis of rotation.
- Torque is a measure of the ability of a force to cause rotational motion and depends on the magnitude and direction of the applied force relative to the axis of rotation.
- Newton's second law for rotational motion states that torque is equal to the moment of inertia times angular acceleration.
The document discusses transistors and transistor amplifiers. It describes the basics of NPN and PNP transistors, including their symbols and how current flows. It then explains common base and common emitter configurations, showing the transistor characteristics and how they function as amplifiers in each configuration. The key gains of current, voltage, and power are also defined for common base amplifiers.
Respiration is the process of oxidizing organic compounds to release energy. In plants, gas exchange occurs through stomata, while in animals it occurs through a specialized respiratory system. The lungs are the main organs of respiration in humans. They are located in the thoracic cavity and have an elastic structure with alveoli that maximize surface area for gas exchange. Oxygen and carbon dioxide diffuse between the alveoli and blood based on partial pressure gradients, with oxygen moving into the blood and carbon dioxide moving out.
This document provides an outline for a semester-long general education physics course titled "Physics For Everyone". It includes an introduction to the course materials and objectives, as well as a week-by-week outline of the course topics, key points to be covered each week, assignments, and recommended online video resources for each topic. The course aims to make physics accessible and relevant for all students using a variety of open educational resources.
Chemistry was the subject of a document dated December 9th, 2019. The document was addressed to Prof. Rajnikant Bhatt of Bhavan's College of Science and Commerce located in Andheri. The document likely concerned a chemistry-related topic but provided no other details.
How to Add Chatter in the odoo 17 ERP ModuleCeline George
In Odoo, the chatter is like a chat tool that helps you work together on records. You can leave notes and track things, making it easier to talk with your team and partners. Inside chatter, all communication history, activity, and changes will be displayed.
हिंदी वर्णमाला पीपीटी, hindi alphabet PPT presentation, hindi varnamala PPT, Hindi Varnamala pdf, हिंदी स्वर, हिंदी व्यंजन, sikhiye hindi varnmala, dr. mulla adam ali, hindi language and literature, hindi alphabet with drawing, hindi alphabet pdf, hindi varnamala for childrens, hindi language, hindi varnamala practice for kids, https://www.drmullaadamali.com
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
Exploiting Artificial Intelligence for Empowering Researchers and Faculty, In...Dr. Vinod Kumar Kanvaria
Exploiting Artificial Intelligence for Empowering Researchers and Faculty,
International FDP on Fundamentals of Research in Social Sciences
at Integral University, Lucknow, 06.06.2024
By Dr. Vinod Kumar Kanvaria
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
This slide is special for master students (MIBS & MIFB) in UUM. Also useful for readers who are interested in the topic of contemporary Islamic banking.
Walmart Business+ and Spark Good for Nonprofits.pdfTechSoup
"Learn about all the ways Walmart supports nonprofit organizations.
You will hear from Liz Willett, the Head of Nonprofits, and hear about what Walmart is doing to help nonprofits, including Walmart Business and Spark Good. Walmart Business+ is a new offer for nonprofits that offers discounts and also streamlines nonprofits order and expense tracking, saving time and money.
The webinar may also give some examples on how nonprofits can best leverage Walmart Business+.
The event will cover the following::
Walmart Business + (https://business.walmart.com/plus) is a new shopping experience for nonprofits, schools, and local business customers that connects an exclusive online shopping experience to stores. Benefits include free delivery and shipping, a 'Spend Analytics” feature, special discounts, deals and tax-exempt shopping.
Special TechSoup offer for a free 180 days membership, and up to $150 in discounts on eligible orders.
Spark Good (walmart.com/sparkgood) is a charitable platform that enables nonprofits to receive donations directly from customers and associates.
Answers about how you can do more with Walmart!"
How to Fix the Import Error in the Odoo 17Celine George
An import error occurs when a program fails to import a module or library, disrupting its execution. In languages like Python, this issue arises when the specified module cannot be found or accessed, hindering the program's functionality. Resolving import errors is crucial for maintaining smooth software operation and uninterrupted development processes.
Executive Directors Chat Leveraging AI for Diversity, Equity, and InclusionTechSoup
Let’s explore the intersection of technology and equity in the final session of our DEI series. Discover how AI tools, like ChatGPT, can be used to support and enhance your nonprofit's DEI initiatives. Participants will gain insights into practical AI applications and get tips for leveraging technology to advance their DEI goals.
3. 3
15.1 Introduction:
1) Leucippus and Democritus- Every matter
indivisible particles called Atoms.
2)J.Dalton - 1.matter is made of indestructible particles.
2.Atoms of given element are identical. 3.Combination
of atoms form new substance.
3)J.J.Thomson -
4)E.Rutherford-
5)N.Bohr-
is made of
4. 4
15.2 THOMSON’S ATOMIC MODEL :
Glass vacuum tube experiment:
• If voltage is applied across cathode and anode then electrons are emitted
by the cathode.
Plum-pudding model of atom:
• Atom is positively charged sphere in which negatively charged electrons
are embedded.
• In atom, the total positive charge is equal to total negative charge
5. 15.3 GEIGER – MARSDEN EXPERIMENT :
• Diagram:
Observations:
• Most of α particles passes through gold foil without deviation.
• Few α particles are deflected through various angles.
• Very few are reflected back from gold foil.
5
6. 6
15.4 RUTHERFORD ATOMIC MODEL :
• Every atom consist of a positively charged core called nucleus.
• Total mass and positive charge of atom is confined in the nucleus.
• The negatively charged electrons are revolving around the nucleus in circular orbits.
• The total positive charge on nucleus is equal to the total negative charge on revolving electrons.
• The size of nucleus is very small as compared to size of atom.
LIMITATIONS:
• It could not explain stability of atom.
• It could not explain origin of atomic spectra(line spectra).
7. 15.6 N.BOHR’S ATOMIC MODEL :
• The electrons revolves around the nucleus in circular orbits.
• The radius of orbit of an electrons can only take certain fixed values such that the angular momentum of
electron in these orbit is an integral multiple of h/2π.(h=planks constant)
• Electron can make transition from one its orbit to another orbit having lower energy. here it emits a photon
of energy equal to difference between energies of two orbits.
7
8. 15.6.1 Radii of the orbits :
By using Bohr’s theory
from above equations, we get
here radius of Bohr’s orbit is directly proportional to square of principle quantum number.
8
9. 15.6.2 ENERGY OF THE ELECTRONS :
• The total energy of an orbiting electron is the sum of its kinetic enrgy and its
electrostatic potential energy. Thus ,
En = K.E. + P.E. , En being the total energy of electron in nth orbit
𝐸𝑛 = 𝑒 𝑛
1 𝑍𝑒2
2 4𝜋𝜀0𝑟𝑏
9
𝑚 𝑣2 + (− )
• The ionization energy of an atom is the minimum amount of energy required
to be given to an electron in ground state of that atom to set the electron free.
It is the binding energy of the hydrogen atom
11. 11
15.6.3 LIMITATIONS OF BOHR’S MODEL :
• It could not explain the line spectra of the atoms other than hydrogen. Even for
hydrogen , more accurate study of observed spectra showed multiple components
in some lines which could not be explained on the basis of this model.
• The intensities of the emission lines seemed to differ from liner to line ang Bohr’s
model had no explanation for that.
• On theoretical side also the model was not entirely satisfactory as it arbitrarily
assumed orbits following a particular condition to be stable. There was no
theoretical basis for that assumption.
12. 15.6.4 De Broglie’s Explanation :
• De Broglie suggested that instead of considering the orbiting electron inside atom as
particle, we should view them as standing waves.
• As light has dual nature material particles also have dual nature i.e. wave and particle
• Wavelength of De Broglie wave is given by formula,
…….(1)
• The relation between De Broglie wavelength and linear momentum is given by ,
• From equation (1) ,
12
13. • Angular momentum of electron in nth orbit is given by ,
Which is nothing but second postulate of Bohr’s atomic model.
Figure : Standing electron wave for
the 4th orbit of an electron in an
atom
13
14. 15.7 Atomic Nucleus :
15.7.1 Constituent of the Nucleus :
• Atomic nucleus is made up of subatomic particles called proton and neutrons , together
they are called nucleons.
• Mass of proton is about 1836 times that of the electron. mass of neutron is nearly same as
mass of proton but slightly greater than mass of proton.
• Proton is positively charged with magnitude of charge is same as the magnitude of charge
of electron.
• Neutron is electrically neutral.
• The number of protons(/electron in neutral atom) in an atom is called its atomic number
and designated as Z. number of neutron is denoted by N.
• The total number of nucleons in a nucleus is called the mass number of atom and denoted
by
𝑍
A= Z+N, therefore atom of an element is denoted as 𝐴𝑋 symbols for hydrogen, carbon and
oxygen can be written as
1𝐻, 12𝐶, 16𝑂.
1 6 8
• The chemical properties of an atom is decided by the number of electron present in it, i.e.
Z. 14
15. 15
• Isotopes :
Atoms having same number of protons but different number of neutrons are called as
isotopes.
Example :
1] deuterium (1𝐻) and tritium (1𝐻) are isotopes of each hydrogen.
2 3
2] 3𝐻𝑒 and 4𝐻𝑒
2 2
• Isobars:
The atom having same mass number A, are called isobars.
Example :
3𝐻𝑒 and 3𝐻𝑒 are isobars .
1 2
• Isotones :
Atoms having the same number of neutrons but different value of atomic number Z,
are called isotones
Example:
3𝐻 and 4𝐻𝑒 are isotones .
1 2
16. Units for measuring masses of atoms and
subatomic particles :
• There three different units of measurement of masses:
• First unit is usual kg , in this system masses of electron, proton and neutrons, me, mp and mn
respectively are .
• Kg is not Convenient method for measurement of masses of subatomic particles .therefor, another
unit called the unified atomic mass unit(u) is used.
“ 1 u is equal to the 1/12th of mass of neutral carbon atom having atomic number
12, in its lowest electronic state. ( 1 u =1.6605402 x 10-27 kg)
In this unit the masses of above three particles are
16
17. • The third unit is in terms of amount of energy that their masses are equivalent to.
Unit used for measurement of masses is eV/c2
one atomic mass unit is equal to 931.5 MeV/c2
The masses of three particles in this unit are
17
18. 15.7.2 Sizes of Nuclei :
•The size of nucleus depends on the number of nucleons present in it i.e. on its atomic number A.
From experimental observations it is found that the radius Rx of a nucleus X is related to the A as
Rx = R0 A1/3 ,
The density ρ inside a nucleus is given by
Where R0 = 1.2 x 10-15 m
Where m = average mass of nucleons. Density is then given as
Putting the value of Rx ,we get
• Thus the density of a nucleus does not depend on the atomic number of the nucleus and is the same for all
nuclei.
the value of nuclear density is ρ = 2.3 x 10 17 kgm-3
18
19. 19
15.7.3 Nuclear Forces :
• Out of these four , the force that determines the structure of the nucleus is the strong force ,
also called the nuclear force.
• This act between proton and neutrons and mostly attractive.
PROPERTIES :
1. It is the strongest force among subatomic particles. Its strength is 50-60 times larger than
that of the electrostatic force of attraction.
2. The nuclear force has a range of about a few fm and the force is negligible when two
nucleons are separated by larger distance.
3. Nuclear force is independent of the charge of the nucleons
20. 15.8 Nuclear Binding Energy :-
• Amount of energy required to separate the nucleons from each other and take them to a large
distance is called the binding energy.
Binding energy is given by,
Where is called mass defect and given by formula,
Here , Z = atomic number
N = neutron number
M = mass of proton
mp = mass of proton
mn = mass of neutron
20
21. • Binding energy per nucleon as a function of mass number :
• EB/A can be used to compare the stabilities of
nuclei. Higher the EB/A value higher the
stability.
• Binding energy per nucleon for different values
of A are plotted in figure shown.
• Deuterium nucleus has the minimum value of
EB/A and is therefore, the least stable nuclei.
• The value of EB/A increases with increase
atomic number and reaches plateau for A
between 50 to 80 . Thus nuclei of these
elements are the most stable among all the
species.
• The peak occurs around A = 56 corresponds to
the iron , which is thus most stable nuclei.
• The value of EB/A decreases gradually for values
of A greater than 80. making the nuclei of those
elements slightly less stable.
• binding energy of hydrogen nucleus having a
single proton is zero. 21
22. 22
15.9 Radioactive Decays:-
• Many of the nuclei are stable i.e. they can remain unchanged for a very long time. Other nuclei
occurring in nature , are not stable and undergoes changes in their structure by emission of
some particle. They change or decay to other nuclei in the process. The decaying nucleus is
called the parent nucleus while the nucleus produced after the decay is called the daughter
nucleus. The process is called radioactive decay or radioactivity.
Alpha Decay :
• In this type of decay, the parent nucleus emits an alpha particle which is the nucleus of
helium atom. The parent nucleus thus loses two proton and two neutrons. The decay
can be expressed as
𝑧 𝑍−2
𝐴𝑋 → 𝐴−4𝑌 + α
Example :
83 81
212𝐵𝑖 → 208𝑇𝑙 + α
23. • the total mass of the product of an alpha decay is always less than the mass of the parent atom. The
excess mass appears as the kinetic energy of the product.
• The difference in the energy equivalent of the mass of the parent atom and that of the sum of masses of
the products is called the Q-value.
• Q value of the decay is equal to the kinetic energy of the products and can be written as
mX, mY and mHe are the masses of the parent atom, the daughter atom and the helium atom.
Beta Decay :
• In this type of decay the nucleus emits an electron produced by converting a neutron in the nucleus
into a proton. The basic process which takes place inside the parent nucleus is
n p + e- + antineutrino
Neutrino and antineutrino are the particles which have very little mass and no change.
• In beta decay there is no change in mass number but atomic number is increased by one.
23
24. • There is another type of beta decay called the beta plus decay in which a proton gets converted to a
neutron by emitting a positron and a neutrino.
• Positron is a particle with the same properties as an electron except that its charge is positive. It is
known as the antiparticle of electron. This decay can be written as,
p n + e+ +neutrino
In this process mass number remains unchanged during the decay but atomic number(Z)
decreases by one. Neutron number(N) increases by one.
The decay can be written as
This decay cannot takes place for a free electron. It can takes place for a proton is inside the nucleus
as the extra energy needed to produce a neutron can be obtained from the rest of the nucleus.
The Q value for the decay can be written as ,
24
25. 25
Gamma Decay :
• In this type of decay, gamma rays are emitted by the parent nucleus. Gamma ray are high energy
photons.
• The daughter nucleus is same as the parent nucleus as no other particle is emitted, but it has less energy
as some energy goes out in the form of the emitted gamma ray.
• Similar to the electrons , the nucleons occupy energy levels with different energies in nucleus. A
Nucleon can make a transition from a higher energy level to a lower energy level, emitting a photon in
the process.
• This energy difference in atom is of few eV’s but for nucleus this difference is of few KeV’s MeV’s .
Therefore radiations emitted by the atom are in the ultraviolet to radio region, the radiations emitted by
nuclei are in the range of gamma rays.
• Usually gamma decay occur after alpha or beta decay , because gamma decay requires large amount of
energy for excitation of nucleus . A nucleon end up in an excited state as a result of the parent nucleus
undergoing alpha or beta decay.
Example : 57Co undergoes beta plus decay to form the daughter nucleus 57Fe which is in excited state
having energy of 136 KeV. This excited nucleus make transition to the ground state by emitting gamma
rays .
26. 15.10 Law of Radioactive decay :
Law of Radioactive decay : At any instant, the rate of radioactive disintegration is directly
proportional to the number of nuclei of the radioactive element present at that instant.
Derivation :Let N0 be the number of nuclei present at time t=0 and N the number of nuclei present
at time t.
𝑑
𝑡
From the law of radioactive decay, 𝑑𝑁
α N
𝑑
𝑡
⸫ 𝑑𝑁
= -λN
𝑁
⸫ 𝑑𝑁
= -λ dt …. (i)
Where, λ is a constant of proportionality called the radioactive decay constant or the disintegration
constant.it is a constant for a particular radioactive element. The minus sign indicates that N
decreases as t increases.
Integrating equation (i)
0 0 0
𝑁ο 𝑡 𝑡
𝑑𝑁/𝑁= - λdt = -λ 𝑑t
⸫ loge N – loge N0 = -λt
⸫ loge{ 𝑁
} = - λt …..(ii)
⸫
𝑁
𝑁0
𝑁0
= e-λt
⸫ N = N0 e –λt
This is the exponential form of the law of radioactive decay, it shows that the number of nuclei
present decreases exponentially with time.
26
27. The activity of a radioactive element is equal to its rate of designation. In other word we can
say that, number of decays per unit time is called as activity A(t) and is given by
Activity (A) = (-dN/dt)
Activity of the sample after time t,
A= A0 e –λt
Its SI unit is Becquerel (Bq)
Its other units are Curie and Rutherford.
1 Curie = 3.7 X 1010 decay/s
1 Rutherford = 106 decay/s
27
Activity of a Radioactive Element :
28. 28
15.10.1 Half-life of Radioactive Material :
• The time taken for the number of parent radioactive nuclei of a particular spices to reduce to half
its value is called the half-life T1/2 of the species.
This can be obtained from equation
N (t) = N0e-λt
eλT1/2 = 2
or T1/2 = log 2
= 0.693
λ λ
• In the half-life is that even though the number goes down from N0 to N0 /2 in time T1/2, after
another time interval T1/2 the number of parent nuclei will not go to zero.
• It will go to half of the value at t = T1/2 i.e. to N0 /4.Thus,in a time interval equal to half-life, the
number of parent nuclei reduces by a factor of ½.
29. Average life or mean life (τ) of a radioactive element is the ratio of total life time of all the atoms
and total number of atoms present initially in the sample.
The number of nuclei decaying between time t and t+dt is given by λN0e-λt dt The life time of
these nuclei is t. thus the average lifetime of a nucleus is
τ =
𝑁 0
0 0
1 ∞ ∞
𝑡λN e-λt dt = λ
𝑡e−λt 𝑑𝑡
Int0
egrating the above we get
τ = 1
λ
The relation between the average life and half life can be obtained as
T1/2 = τlog2 =0.693τ
15.11 Nuclear Energy :
15.10.2 Average Life of Radioactive Species :
• Nuclear energy is the energy released when nuclei undergo a nuclear reaction i.e.
when one nucleus or a pair of nuclei, due to their interaction, undergo a change in
their structure resulting in new nuclei and generating energy in the process.
We can obtain nuclear energy by two other processes
i) nuclear fission in which a heavy nucleus is broken into two nuclei of smaller masses
and
ii) nuclear fusion in which two light nuclei undergo nuclear reaction and fuse together
to form a heavier nucleus. 29
30. • The process of the splitting of a heavy nucleus into two or more lighter nuclei is called nuclear
fission.
When a slow moving neutron strikes with a uranium nucleus a (92U235) it splits into (56Ba141)and
(36Kr92)along with three neutrons and a lot of energy.
15.11.2 Nuclear Fusion :
The process of combining of two lighter nuclei to form one heavy nucleus is called nuclear fusion.
In this process a large amount of energy is released.
Nuclear fusion takes place at very high temperature approximately about 107 K and at very high pressure
106 atmosphere.
Hydrogen bomb is based on nuclear fusion.
30
15.11.1 Nuclear Fission :
31. • A nuclear reactor is an apparatus or a device in which nuclear fission is carried out in a controlled
manner to produce energy in the form of heat which is then converted to electricity.
• In uranium reactor, 92U235 is used as the fuel. It is bombarded by slow neutrons to produce 92U236
which undergoes fission.
Nuclear Chain Reaction :
If the particle starting the nuclear fission reaction is produced as a product and further take
part in the nuclear fission reaction, then a chain of fission reaction started, which is called
nuclear chain reaction.
Nuclear chain reaction are of two types
i) controlled chain reaction
ii) uncontrolled chain reaction.
31
Uranium Nuclear Reactor :
32. Question Bank
Multiple choice questions ( one mark questions)
1) Rate of disintegration of radioactive nucleus is affected by……..
a) temperature
c) external electric or magnetic field
2) In a radioactive decay………
a) only charged material particles are emitted
c) charged material particles as well as energy is emitted
3) Half life of an element depends upon…….
b) pressure
d) none of the above
b) only energy is emitted
d) nothing is emitted
a) original amount
c) temperature
b)external pressure
d)none of the above
4)A radioactive substance has half-life of 4 days. Time required for 31/32 of the original amount to
disintegrate
is……
a) 4 days b)16 days c)20 days d)24 days
5) A radioactive element decays to 1/8th of its initial amount in 75 days. The half life of the element is………
a) 37.5 days b)6.5 days c) 25 days d) 12.5 days
Answer keys:- 1) d 2) c 3) d 4) c 5) c
32
33. 33
Q. Define the following terms.
(1 mark)
1. Ionization energy
2. Isotopes
3. Isobars
4. Isotone
5. Mass defect
6. Binding energy of nucleus
7. Radioactive decay
8. Q- value
9. Radioactivity
10. decay constant
11. Half life period
34. 34
Two Marks Questions :-
1. State postulates of Bohr’s atomic model.
2. State difficulties faced by Rutherford atomic model.
3. Derive the formula for half life period.
4. State and explain nuclear fission.
5. State and explain nuclear fusion.
6. Prove that nuclear density is same for all nuclei.
7. Define binding energy of nucleon and write its expression.
35. 35
Three Marks Question :-
1. Derive the expression for energy of electron in atom.
2. State limitations of Bohr’s atomic theory.
3. State the law of radioactive decay. Derive the formula.
4.Define decay constant and show that it is reciprocal of time duration (t) in which the
substance decays to 37% of its original quantity.
5. Define binding energy of nucleon. State its significance.
6. State types of radioactivity. OR what are alpha, beta and gamma decay.
7. Draw a binding energy curve to show the variation of binding energy per nucleon with
mass number. What are the conclusions can be drawn from B.E curve?
36. Numerical:-
1.
36
2.
• HINT:
Given: mAm = 244.06428 u ; AAm = 244 ,
N(P) = 95 , N(n) = 244 -95 =149
To find : Binding energy per nucleon(EB/A)
Formula : EB = [∆M]c2
• HINT:
Use : Q = [∆M]c2 in each case.
i. Q = [Mra-Mpb-MC]c2
ii. Q = [MU-MBa-MKr-2 x mn]c2
C B e+
iii. Q = [M -M -M ]c2
2.
37. 3.
4.
• HINT: Aavg mass of Mg = 24.312 u:
Formula;
Avg mass og Mg =m(24
12𝑀𝑔) x 78.99
+ m(25
100 12𝑀𝑔) x 𝑥
100
+
12
m(26𝑀𝑔) x 21.01−𝑥
100
Isotope Mass(u) Abundance(%)
24𝑀𝑔
12 23.98504 78.99
25𝑀𝑔
12 24.98548 x
26𝑀𝑔
12 25.98259 (21.01 – x)
• 𝐻𝐼𝑁𝑇: 𝐸𝐵 = ∆𝑀 𝐶2 , ∆𝑀 = 𝑍𝑀𝑃 + 𝑁𝑚𝑛 − 𝑀
= 2𝑚𝑃 + 2𝑚𝑛 − 𝑚𝛼
5.
• HINT: To find, Energy released in
the nuclear reaction. (Q value)
𝑄 = 𝑚𝑝𝑎𝑟𝑒𝑛𝑡 − 𝑚𝑝𝑟𝑜𝑑𝑢𝑐𝑡 𝑐2
= [𝑚𝐿𝑖 + 𝑚𝑃 − 2𝑚𝛼]𝑐2
37
38. 38
6. Activity of a radioactive element is reduced by 0.75 of its initial value in 2.5 years. Find decay
constant.
ANS: 0.5546year-1
Hint –N=N0e-λt,
7. The decay constant of radioactive substance is 4.33 x 10-4
per year. Calculate its half life.
ANS: 1600 years
Hint T=0.693/λ ,
39. 9. Sample of carbon obtained from any living organism has a decay rate of 15.3 decays per gram per
minute.
A sample of carbon obtained from very old charcoal shows a disintegration rate of 12.3
disintegrations per gram
per minute. Determine the age of the old sample given the decay constant of carbon to be 3.839 x
10 -12 per second .
ANS: 1803 years
𝑑
𝑡
0
HINT: 𝐴 𝑡 = − 𝑑𝑁
= λ𝑁 𝑡 = λ𝑁 𝑒−λ𝑡, 𝐴0 = λ𝑁0𝑒−𝜆 0
39
= λ𝑁0
88
8. The half life of Ra is
226
1620 𝑦 .Find its decay constant in SI unit.
(Hint T=0.693/λ )
ANS: 1.356 X 10-11 s-1
40. 40
10. Complete the following equations describing nuclear decay
88
a. 226𝑅𝑎 → 𝛼 + … … …
8
b. 19𝑂 → 𝑒− + … … …
90
c. 228𝑇ℎ → 𝛼 + … … …
d. 12𝑁 → 12𝐶 + … … …
7 6
Solution:
a. 226𝑅𝑎 → 𝛼 + 𝟐𝟐𝟔𝑹𝒏
88 𝟖𝟔
b. 19𝑂 → 𝑒− + 𝟏𝟗𝑭
8 𝟗
c. 228𝑇ℎ → 𝛼 + 𝟐𝟐𝟔𝑹𝒂
90 𝟖𝟖
d. 12𝑁 → 12𝐶 + 𝒆+
7 6
41. 11. Disintegration rate of a sample is 1010 per hour at 20 hrs from the start. It reduces to 6.3
x 109 per hours after 30 hours . Calculate its half-life and the initial number of radioactive
atoms in the sample.
ANS: 15 hrs , 5.45 x 1011
𝑑
𝑡
0
HINT: : 𝐴 𝑡 = − 𝑑𝑁
= λ𝑁 𝑡 = λ𝑁 𝑒−λ𝑡, 𝐴0 = λ𝑁0𝑒−𝜆 0 = λ𝑁0
15
2
12. A source contains two species of phosphorous nuclei, 32𝑃 (𝑇1 = 14.3 𝑑𝑎𝑦𝑠) and
15
2
32𝑃 (𝑇1 = 14.3 𝑑𝑎𝑦𝑠) .
15
At time t = 0, 90% of the decays are from 32𝑃. How much time has to elapsed for only 15% of the
15
decays to be from 32𝑃 ?
ANS: 186.6 d
HINT: find λ1 𝑎𝑛𝑑 λ2 by using formula λ =
0.693
𝑇
𝑑
𝑡
0
41
: 𝐴 𝑡 = − 𝑑𝑁
= λ𝑁 𝑡 = λ𝑁 𝑒−λ𝑡,
42. Portion deleted due to Covid-19 for the year 2020-2021
42
Sr.no Page Number . Article
01 324 15.3 Geiger Marsden
experiment
02 330-332 15.7 Atomic nucleus
03 332-333 15.8 Nuclear binding energy
04 333-336 15.9 Radioactive decay
05 338-341 15.11 Nuclear energy
43. 43
Topic: Structure of Atom and Nuclei
PPT Presentation By-
- Mr. Mote D.P.
New Model Junior
college , Kolhapur.
- Mr. Halli S.A.
New Model Junior
college , Kolhapur.
- Mr. KirdatN.S.
Shri. Venna Vidyamandirand
JuniorCollege, Medha, Satara