The document summarizes the structure of an atom in 3 paragraphs:
1) It describes the three main subatomic particles - electrons, protons, and neutrons - and their relative masses and charges.
2) It outlines the historical discoveries of these particles, including Thomson discovering electrons in 1900, discoveries of positively charged particles (protons) in the late 1800s, and Chadwick discovering neutrons in 1932.
3) It discusses several historical models of the atom, including Thomson's "plum pudding" model, Rutherford's discovery of the nucleus from alpha scattering experiments, and Bohr's improvement adding discrete electron orbits that explained atomic stability.
Chemical Structure: Structure of Matter. Atoms – the building blocks of matterulcerd
Lecture materials for the Introductory Chemistry course for Forensic Scientists, University of Lincoln, UK. See http://forensicchemistry.lincoln.ac.uk/ for more details.
The document discusses the structure of atoms. It explains that atoms contain protons, neutrons and electrons. The atomic model has evolved over time from Thomson's "plum pudding" model to Rutherford's discovery of the nucleus at the center of the atom, to Bohr's model of electrons in discrete orbits. It further discusses the distribution of electrons in different shells, an element's valency which is determined by its outer shell electrons, atomic and mass numbers, isotopes and isobars.
This document provides information about atomic structure. It discusses the three main subatomic particles - electrons, protons, and neutrons. It describes the discoveries of these particles by scientists like J.J. Thomson, E. Goldstein, and Chadwick. Models of the atom proposed by scientists like Thomson, Rutherford, and Bohr are explained. The distribution of electrons in different shells is given according to Bohr's model. Information about isotopes, isobars, and valency is also provided.
J.J. Thomson proposed the plum pudding model where electrons were embedded in a uniform sphere of positive charge, making the atom electrically neutral. However, Rutherford's gold foil experiment found that most alpha particles passed through, but some were deflected at very large angles. This led Rutherford to propose that the positive charge and mass of an atom are concentrated in a very small nucleus, with electrons orbiting the outside. This nuclear model of the atom replaced Thomson's plum pudding model.
This document provides a summary of the structure of the atom. It discusses the three main subatomic particles - electrons, protons, and neutrons. It then describes the historical models of the atom including Thomson's plum pudding model, Rutherford's nuclear model, and Bohr's orbital model. Key topics covered include the distribution of electrons in shells, atomic number, mass number, isotopes, isobars, and valency.
This document provides an overview of atomic structure and the development of atomic theory. It discusses the basic composition of atoms, including electrons, protons, and neutrons. It describes Dalton's atomic theory and the key postulates. It also discusses subatomic particles like isotopes, ions, and the discovery of electrons, protons, and neutrons through experiments. The document is divided into sections on the composition of atoms, atomic calculations, isotopes, ions, atomic mass, and the development of atomic theory from Dalton to the discovery of subatomic particles.
- Atoms contain positively charged protons, uncharged neutrons, and negatively charged electrons. Electrons orbit the small, dense nucleus that contains protons and neutrons.
- Rutherford's gold foil experiment showed that the atom consists mostly of empty space, with a small, dense nucleus at the center containing most of the atom's mass.
- Electrons orbit the nucleus in distinct energy levels or shells, allowing atoms to be stable without electrons losing energy through radiation.
1) Chemical bonds can be either ionic or covalent. Ionic bonds form when electrons are transferred between metals and non-metals to form ions. Covalent bonds form when electrons are shared between non-metals.
2) Sodium chloride forms when sodium donates an electron to chlorine to form ions that are attracted in an ionic bond. Hydrogen molecule forms when hydrogen atoms share an electron pair in a single covalent bond.
3) Ionic compounds have high melting points, conduct electricity when molten or dissolved, and dissolve in water but not organic solvents. Covalent compounds have lower melting points, do not conduct electricity, and dissolve in organic solvents but not water.
Chemical Structure: Structure of Matter. Atoms – the building blocks of matterulcerd
Lecture materials for the Introductory Chemistry course for Forensic Scientists, University of Lincoln, UK. See http://forensicchemistry.lincoln.ac.uk/ for more details.
The document discusses the structure of atoms. It explains that atoms contain protons, neutrons and electrons. The atomic model has evolved over time from Thomson's "plum pudding" model to Rutherford's discovery of the nucleus at the center of the atom, to Bohr's model of electrons in discrete orbits. It further discusses the distribution of electrons in different shells, an element's valency which is determined by its outer shell electrons, atomic and mass numbers, isotopes and isobars.
This document provides information about atomic structure. It discusses the three main subatomic particles - electrons, protons, and neutrons. It describes the discoveries of these particles by scientists like J.J. Thomson, E. Goldstein, and Chadwick. Models of the atom proposed by scientists like Thomson, Rutherford, and Bohr are explained. The distribution of electrons in different shells is given according to Bohr's model. Information about isotopes, isobars, and valency is also provided.
J.J. Thomson proposed the plum pudding model where electrons were embedded in a uniform sphere of positive charge, making the atom electrically neutral. However, Rutherford's gold foil experiment found that most alpha particles passed through, but some were deflected at very large angles. This led Rutherford to propose that the positive charge and mass of an atom are concentrated in a very small nucleus, with electrons orbiting the outside. This nuclear model of the atom replaced Thomson's plum pudding model.
This document provides a summary of the structure of the atom. It discusses the three main subatomic particles - electrons, protons, and neutrons. It then describes the historical models of the atom including Thomson's plum pudding model, Rutherford's nuclear model, and Bohr's orbital model. Key topics covered include the distribution of electrons in shells, atomic number, mass number, isotopes, isobars, and valency.
This document provides an overview of atomic structure and the development of atomic theory. It discusses the basic composition of atoms, including electrons, protons, and neutrons. It describes Dalton's atomic theory and the key postulates. It also discusses subatomic particles like isotopes, ions, and the discovery of electrons, protons, and neutrons through experiments. The document is divided into sections on the composition of atoms, atomic calculations, isotopes, ions, atomic mass, and the development of atomic theory from Dalton to the discovery of subatomic particles.
- Atoms contain positively charged protons, uncharged neutrons, and negatively charged electrons. Electrons orbit the small, dense nucleus that contains protons and neutrons.
- Rutherford's gold foil experiment showed that the atom consists mostly of empty space, with a small, dense nucleus at the center containing most of the atom's mass.
- Electrons orbit the nucleus in distinct energy levels or shells, allowing atoms to be stable without electrons losing energy through radiation.
1) Chemical bonds can be either ionic or covalent. Ionic bonds form when electrons are transferred between metals and non-metals to form ions. Covalent bonds form when electrons are shared between non-metals.
2) Sodium chloride forms when sodium donates an electron to chlorine to form ions that are attracted in an ionic bond. Hydrogen molecule forms when hydrogen atoms share an electron pair in a single covalent bond.
3) Ionic compounds have high melting points, conduct electricity when molten or dissolved, and dissolve in water but not organic solvents. Covalent compounds have lower melting points, do not conduct electricity, and dissolve in organic solvents but not water.
objective
theory of atom
dalton`theory
Thomson, s model of atom
atomic number and mass number
isotopes, molecules formula, empirical formula
ions, formula of ionic compound, polyatomic ions, chemical nomenclature
The document summarizes key concepts from a chapter on the periodic table, including:
1) It traces the historical development of the periodic table from early classifications of elements by their properties to Dobereiner's discovery of triads of elements and eventual development of the modern periodic table by Mendeleev and Moseley's organization by atomic number.
2) It explains how to read information from the periodic table such as the atomic number, name, and mass of elements as well as trends in various properties that are illustrated in the organization of the table.
3) It describes periodic trends in properties including atomic radius, ionization energy, electron affinity, and electronegativity that help explain elements' chemical behaviors
1. The document discusses atoms, molecules, ions and chemical formulas. It explains concepts like atomic mass, molecular mass, valency and the mole concept.
2. Key points include Dalton's atomic theory, that atoms combine in small whole number ratios to form compounds, and that the mass of elements and compounds can be expressed in atomic mass units or grams.
3. Molecular mass is calculated by adding the atomic masses of each element in a molecule. A mole represents 6.022 x 1023 particles and can be used to relate mass, number of particles, and molar mass.
this ppt is all about basic working of most basic unit atom. and could enrich your knowledge about atom. and follow me at my instagram
https://www.instagram.com/shantanu_stark/?hl=en
This document provides information about the structure of the atom. It discusses the three main subatomic particles - electrons, protons, and neutrons. It describes the discoveries of these particles by scientists like Thomson, Goldstein, and Chadwick. The document then explains four major atomic models - Thomson's model, Rutherford's model, Bohr's model, and the distribution of electrons in shells. It also discusses concepts like atomic number, mass number, isotopes, isobars, and valency.
This document summarizes key concepts about atoms and molecules. It defines an atom as the smallest unit that retains an element's characteristics. Atoms have a nucleus containing protons and neutrons surrounded by an electron cloud. Molecules are defined as stable groups of two or more atoms bonded together, either through ionic bonds formed by electron transfer or covalent bonds formed by electron sharing. Examples of hydrogen, lithium, and argon atoms are provided to illustrate their atomic structure. Isotopes are also introduced as atoms of the same element with different numbers of neutrons.
This document discusses key concepts in atomic structure and bonding:
1. It describes John Dalton's atomic theory and the discoveries of J.J. Thomson, Ernest Rutherford, and other scientists that led to developing the modern atomic model.
2. Key aspects of the modern atomic model are explained, including that atoms are composed of protons, neutrons, and electrons, with the nucleus at the center containing protons and neutrons.
3. The document also introduces concepts such as isotopes, ions, and how elements are arranged on the periodic table based on their atomic structure.
Hello everyone, I am Dr. Ujwalkumar Trivedi, Head of Biotechnology Department at Marwadi University Rajkot. I teach Molecular Biology to the students of M.Sc. Microbiology and Biotechnology.
The current presentation is about the historical perspectives of the discovery of atoms and subatomic particles. The later part of the presentation describes various atomic models and the properties of subatomic particles with a description of commonly used terms like molecules, ions and compounds.
There are several misconceptions about the valence shell of the atom. The key questions that arise in the minds of the learners are:
Is valence shell really the outermost shell?
2. Are there only seven shells in an atom?
3. When shells are supposed to be made up of subshells, why can we not represent the subshells in the valence shell structure of the atom?
4. When electrons are said to occur in orbitals, why can we not indicate the orbitals in the valence shell structure?
4. How can we represent the origins for valance band and conduction band in the atomic structure?
5. What are some good metaphors for the core of the atom and the rest of the atom?
Here is a lesson created by Chemistry teachers to address these misconceptions.
The document discusses the periodic table of elements and its development over time. It explains how elements are arranged based on their proton number and how this arrangement allows prediction of element properties based on periodic trends. Examples are given of common elements and their uses to illustrate the practical importance of the periodic table.
Atoms are the smallest particles that make up all matter. John Dalton's atomic theory states that all matter is made of tiny indivisible particles called atoms. Atoms of different elements have different masses and chemical properties. Two or more atoms can combine to form molecules, which are the smallest units that retain the properties of a substance. Molecules are formed when atoms bond together via chemical bonds and are the smallest particles that can exist independently. Common examples of molecules include water (H2O) and oxygen (O2).
This document provides a summary of key concepts about atoms and molecules:
1) It defines atoms as the smallest particle of an element that retains chemical properties, and molecules as a group of atoms held together.
2) It explains Dalton's atomic theory, including that atoms combine in small whole number ratios to form compounds.
3) It discusses the symbols and masses of atoms, atomicity and valency, writing chemical formulas, and calculating molecular mass.
4) It introduces the mole concept relating the number of particles, mass, and molar mass.
1. The document discusses key concepts relating to atoms, molecules, ions, and chemical formulas. It covers Dalton's atomic theory, isotopes, relative atomic mass, ion formation, and rules for writing chemical formulas.
2. The main topics covered include the basic structure of atoms and molecules, including that atoms combine in whole number ratios to form compounds. It also addresses limitations of Dalton's theory regarding isotopes and isobars.
3. The document defines important terms like molecules, ions, valency, and molar mass and explains the relationship between mass and moles of a substance.
Valence electrons are the outermost shell electrons of an atom that are involved in bonding. Elements in the same group on the periodic table have the same number of valence electrons because they exhibit similar chemical properties based on their valence electron configuration. Atoms seek to attain a full outer shell of 8 electrons to achieve stability through gaining, losing or sharing valence electrons in chemical bonds.
This document provides an overview of physical science concepts related to subatomic particles, the periodic table, oxidation numbers, and Lewis dot diagrams. The key points are:
1) It reviews subatomic particles, periods and groups of the periodic table, and electron configurations.
2) The objective is to predict oxidation numbers and draw Lewis dot diagrams by understanding valence electrons.
3) It defines valence electrons, oxidation numbers, and ionic bonds in chemical compounds.
4) Examples are given of writing chemical symbols, determining valence electrons, and drawing Lewis dot diagrams using the cross method.
A PERFECT POWERPOINT PRESENTATION FOR CHAPTER ATOMS AND MOLECULES FOR CLASS 9. IT COVERS ALL THE MAJOR CONCEPTS AND TOPICS OF THE CHAPTER. HOPE YOU LIKE IT.
- Matter is composed of particles called atoms and molecules. Atoms are the smallest particles that make up elements, and molecules are made of two or more bonded atoms.
- The structure of the atom has been discovered over time by scientists like Dalton, Thomson, Rutherford, Bohr, and Chadwick. We now know atoms have a tiny, dense nucleus containing protons and neutrons, surrounded by electrons.
- Isotopes are atoms of the same element with different numbers of neutrons. Some isotopes are unstable and radioactive, while others are stable. Radioactive isotopes have important applications in medicine, agriculture, and industry.
The document summarizes key concepts about the periodic table, including:
1) The periodic table organizes elements horizontally by period and vertically by group, with elements in the same group having similar properties.
2) Elements are classified as metals, nonmetals, and metalloids based on their properties, with metals generally conducting heat/electricity and nonmetals not.
3) Periodic trends show atomic radius decreases but ionization energy, electronegativity, and ionic size increase moving left to right across a period.
This document discusses how to determine if an atom is a metal or non-metal based on its valence electrons, and describes the formation of ionic and covalent bonds. Ionic bonds form between metal and non-metal atoms through the transfer of electrons from the metal to the non-metal. Covalent bonds form between non-metal atoms through the sharing of electrons. Examples of ionic bond formation in sodium chloride and covalent bond formation in carbon dioxide are provided, along with electron diagrams to illustrate bonding.
- Isotopes are atoms of the same element that have different numbers of neutrons. Some isotopes are radioactive while others are non-radioactive.
- Radioactive isotopes can be useful in medical applications like cancer treatment and dating ancient remains, as well as industrial uses like leak detection. Their half-lives determine how long it takes for half of a sample to decay.
- Atoms gain and lose electrons to form ions, and ionic bonds form between oppositely charged ions. Ionic compounds have high melting points and are usually soluble in water.
This document summarizes the structure of the atom. It discusses the three main subatomic particles - electrons, protons, and neutrons. It describes the discoveries of these particles by scientists like Thomson, Goldstein, and Chadwick. The document then summarizes four major atomic models - Thomson's model, Rutherford's model, Bohr's model, and the distribution of electrons in shells. It also discusses concepts like atomic number, mass number, isotopes, isobars, and valency.
1) Atoms contain positively charged protons, neutral neutrons, and negatively charged electrons. Electrons orbit the dense, positively charged nucleus at the center of the atom.
2) Rutherford discovered the nucleus through alpha particle scattering experiments. His model showed electrons orbiting the tiny, dense nucleus. Bohr added that electrons can only orbit in discrete energy levels.
3) Elements are defined by their atomic number, or number of protons. Isotopes are atoms of the same element with different numbers of neutrons, giving them different mass numbers.
objective
theory of atom
dalton`theory
Thomson, s model of atom
atomic number and mass number
isotopes, molecules formula, empirical formula
ions, formula of ionic compound, polyatomic ions, chemical nomenclature
The document summarizes key concepts from a chapter on the periodic table, including:
1) It traces the historical development of the periodic table from early classifications of elements by their properties to Dobereiner's discovery of triads of elements and eventual development of the modern periodic table by Mendeleev and Moseley's organization by atomic number.
2) It explains how to read information from the periodic table such as the atomic number, name, and mass of elements as well as trends in various properties that are illustrated in the organization of the table.
3) It describes periodic trends in properties including atomic radius, ionization energy, electron affinity, and electronegativity that help explain elements' chemical behaviors
1. The document discusses atoms, molecules, ions and chemical formulas. It explains concepts like atomic mass, molecular mass, valency and the mole concept.
2. Key points include Dalton's atomic theory, that atoms combine in small whole number ratios to form compounds, and that the mass of elements and compounds can be expressed in atomic mass units or grams.
3. Molecular mass is calculated by adding the atomic masses of each element in a molecule. A mole represents 6.022 x 1023 particles and can be used to relate mass, number of particles, and molar mass.
this ppt is all about basic working of most basic unit atom. and could enrich your knowledge about atom. and follow me at my instagram
https://www.instagram.com/shantanu_stark/?hl=en
This document provides information about the structure of the atom. It discusses the three main subatomic particles - electrons, protons, and neutrons. It describes the discoveries of these particles by scientists like Thomson, Goldstein, and Chadwick. The document then explains four major atomic models - Thomson's model, Rutherford's model, Bohr's model, and the distribution of electrons in shells. It also discusses concepts like atomic number, mass number, isotopes, isobars, and valency.
This document summarizes key concepts about atoms and molecules. It defines an atom as the smallest unit that retains an element's characteristics. Atoms have a nucleus containing protons and neutrons surrounded by an electron cloud. Molecules are defined as stable groups of two or more atoms bonded together, either through ionic bonds formed by electron transfer or covalent bonds formed by electron sharing. Examples of hydrogen, lithium, and argon atoms are provided to illustrate their atomic structure. Isotopes are also introduced as atoms of the same element with different numbers of neutrons.
This document discusses key concepts in atomic structure and bonding:
1. It describes John Dalton's atomic theory and the discoveries of J.J. Thomson, Ernest Rutherford, and other scientists that led to developing the modern atomic model.
2. Key aspects of the modern atomic model are explained, including that atoms are composed of protons, neutrons, and electrons, with the nucleus at the center containing protons and neutrons.
3. The document also introduces concepts such as isotopes, ions, and how elements are arranged on the periodic table based on their atomic structure.
Hello everyone, I am Dr. Ujwalkumar Trivedi, Head of Biotechnology Department at Marwadi University Rajkot. I teach Molecular Biology to the students of M.Sc. Microbiology and Biotechnology.
The current presentation is about the historical perspectives of the discovery of atoms and subatomic particles. The later part of the presentation describes various atomic models and the properties of subatomic particles with a description of commonly used terms like molecules, ions and compounds.
There are several misconceptions about the valence shell of the atom. The key questions that arise in the minds of the learners are:
Is valence shell really the outermost shell?
2. Are there only seven shells in an atom?
3. When shells are supposed to be made up of subshells, why can we not represent the subshells in the valence shell structure of the atom?
4. When electrons are said to occur in orbitals, why can we not indicate the orbitals in the valence shell structure?
4. How can we represent the origins for valance band and conduction band in the atomic structure?
5. What are some good metaphors for the core of the atom and the rest of the atom?
Here is a lesson created by Chemistry teachers to address these misconceptions.
The document discusses the periodic table of elements and its development over time. It explains how elements are arranged based on their proton number and how this arrangement allows prediction of element properties based on periodic trends. Examples are given of common elements and their uses to illustrate the practical importance of the periodic table.
Atoms are the smallest particles that make up all matter. John Dalton's atomic theory states that all matter is made of tiny indivisible particles called atoms. Atoms of different elements have different masses and chemical properties. Two or more atoms can combine to form molecules, which are the smallest units that retain the properties of a substance. Molecules are formed when atoms bond together via chemical bonds and are the smallest particles that can exist independently. Common examples of molecules include water (H2O) and oxygen (O2).
This document provides a summary of key concepts about atoms and molecules:
1) It defines atoms as the smallest particle of an element that retains chemical properties, and molecules as a group of atoms held together.
2) It explains Dalton's atomic theory, including that atoms combine in small whole number ratios to form compounds.
3) It discusses the symbols and masses of atoms, atomicity and valency, writing chemical formulas, and calculating molecular mass.
4) It introduces the mole concept relating the number of particles, mass, and molar mass.
1. The document discusses key concepts relating to atoms, molecules, ions, and chemical formulas. It covers Dalton's atomic theory, isotopes, relative atomic mass, ion formation, and rules for writing chemical formulas.
2. The main topics covered include the basic structure of atoms and molecules, including that atoms combine in whole number ratios to form compounds. It also addresses limitations of Dalton's theory regarding isotopes and isobars.
3. The document defines important terms like molecules, ions, valency, and molar mass and explains the relationship between mass and moles of a substance.
Valence electrons are the outermost shell electrons of an atom that are involved in bonding. Elements in the same group on the periodic table have the same number of valence electrons because they exhibit similar chemical properties based on their valence electron configuration. Atoms seek to attain a full outer shell of 8 electrons to achieve stability through gaining, losing or sharing valence electrons in chemical bonds.
This document provides an overview of physical science concepts related to subatomic particles, the periodic table, oxidation numbers, and Lewis dot diagrams. The key points are:
1) It reviews subatomic particles, periods and groups of the periodic table, and electron configurations.
2) The objective is to predict oxidation numbers and draw Lewis dot diagrams by understanding valence electrons.
3) It defines valence electrons, oxidation numbers, and ionic bonds in chemical compounds.
4) Examples are given of writing chemical symbols, determining valence electrons, and drawing Lewis dot diagrams using the cross method.
A PERFECT POWERPOINT PRESENTATION FOR CHAPTER ATOMS AND MOLECULES FOR CLASS 9. IT COVERS ALL THE MAJOR CONCEPTS AND TOPICS OF THE CHAPTER. HOPE YOU LIKE IT.
- Matter is composed of particles called atoms and molecules. Atoms are the smallest particles that make up elements, and molecules are made of two or more bonded atoms.
- The structure of the atom has been discovered over time by scientists like Dalton, Thomson, Rutherford, Bohr, and Chadwick. We now know atoms have a tiny, dense nucleus containing protons and neutrons, surrounded by electrons.
- Isotopes are atoms of the same element with different numbers of neutrons. Some isotopes are unstable and radioactive, while others are stable. Radioactive isotopes have important applications in medicine, agriculture, and industry.
The document summarizes key concepts about the periodic table, including:
1) The periodic table organizes elements horizontally by period and vertically by group, with elements in the same group having similar properties.
2) Elements are classified as metals, nonmetals, and metalloids based on their properties, with metals generally conducting heat/electricity and nonmetals not.
3) Periodic trends show atomic radius decreases but ionization energy, electronegativity, and ionic size increase moving left to right across a period.
This document discusses how to determine if an atom is a metal or non-metal based on its valence electrons, and describes the formation of ionic and covalent bonds. Ionic bonds form between metal and non-metal atoms through the transfer of electrons from the metal to the non-metal. Covalent bonds form between non-metal atoms through the sharing of electrons. Examples of ionic bond formation in sodium chloride and covalent bond formation in carbon dioxide are provided, along with electron diagrams to illustrate bonding.
- Isotopes are atoms of the same element that have different numbers of neutrons. Some isotopes are radioactive while others are non-radioactive.
- Radioactive isotopes can be useful in medical applications like cancer treatment and dating ancient remains, as well as industrial uses like leak detection. Their half-lives determine how long it takes for half of a sample to decay.
- Atoms gain and lose electrons to form ions, and ionic bonds form between oppositely charged ions. Ionic compounds have high melting points and are usually soluble in water.
This document summarizes the structure of the atom. It discusses the three main subatomic particles - electrons, protons, and neutrons. It describes the discoveries of these particles by scientists like Thomson, Goldstein, and Chadwick. The document then summarizes four major atomic models - Thomson's model, Rutherford's model, Bohr's model, and the distribution of electrons in shells. It also discusses concepts like atomic number, mass number, isotopes, isobars, and valency.
1) Atoms contain positively charged protons, neutral neutrons, and negatively charged electrons. Electrons orbit the dense, positively charged nucleus at the center of the atom.
2) Rutherford discovered the nucleus through alpha particle scattering experiments. His model showed electrons orbiting the tiny, dense nucleus. Bohr added that electrons can only orbit in discrete energy levels.
3) Elements are defined by their atomic number, or number of protons. Isotopes are atoms of the same element with different numbers of neutrons, giving them different mass numbers.
The document summarizes key concepts about the structure of the atom:
1) Atoms contain positively charged protons, neutral neutrons, and negatively charged electrons. Rutherford discovered the nucleus and that atoms are mostly empty space.
2) Bohr's model improved on Rutherford's by proposing electrons orbit in discrete energy levels.
3) Elements are defined by their atomic number, or number of protons. Isotopes are atoms of the same element with different numbers of neutrons.
The document summarizes key concepts about the structure of the atom. It discusses the three main subatomic particles - electrons, protons, and neutrons. It describes early atomic models proposed by Thomson, Rutherford, and Bohr. Key points of each model are provided. The document also discusses concepts like the distribution of electrons in shells, valency, atomic number, mass number, isotopes, and isobars. In summary, it provides an overview of the historical development of atomic structure and defines important atomic terms.
The document discusses the structure of atoms. It explains that atoms are made up of a nucleus containing protons and neutrons, surrounded by electrons. The number of protons determines the element, while the number of neutrons determines the isotope. Electrons determine chemical properties and are equal to the number of protons. The periodic table arranges elements in order of atomic number and can be used to look up each element's protons, neutrons, and electrons. Isotopes are variants of the same element with different numbers of neutrons. Compounds contain two or more elements chemically bonded together, and their formulas show the number of atoms of each element. The electronic structure shows how electrons fill different energy levels around the nucleus.
The document provides information about the structure of atoms. It discusses that atoms are made up of protons, neutrons and electrons. The protons and neutrons are located in the nucleus at the center, while the electrons move around the nucleus. It explains different atomic models proposed by scientists like Thomson, Rutherford and Bohr. It also discusses the distribution of electrons in shells, valency, atomic number and mass number. Isotopes and isobars are defined. In summary, the document outlines the key particles that make up an atom and the various atomic structure models developed over time.
Atomos, Teorías Atómicas, Teoría Cuántica, Masa Atómica e Isotoposfernandogc
The document provides information about atoms and their subatomic particles. It defines the atom as the smallest particle of an element that retains its characteristics. It describes atoms as consisting of protons, neutrons, and electrons. The number of protons defines the element and its atomic number, while the total of protons and neutrons is the mass number. Isotopes are atoms of the same element with different numbers of neutrons. Electron configuration diagrams show how electrons are arranged in an atom's energy levels.
Ionic bonding occurs when atoms transfer electrons to form ions with opposite charges that are attracted via electrostatic forces. Metals form cations by losing electrons to achieve stable electron configurations like noble gases, while nonmetals form anions by gaining electrons. This transfer of electrons allows the formation of ionic compounds with crystalline structures where ion attractions are maximized and repulsions minimized. Properties of ionic compounds include high melting points, solubility in water, defined crystal structures, and the ability to conduct electricity when molten. Metallic bonding also involves cations but is characterized by delocalized valence electrons that form a "sea" allowing metals to conduct electricity and be malleable and ductile.
This document discusses atomic structure and the modern atomic theory. It covers:
1) Early thinkers like Democritus who proposed atoms and Aristotle who disagreed.
2) John Dalton developed the theory that elements are composed of atoms that combine in fixed ratios.
3) Experiments provided evidence of subatomic particles like the cathode ray tube experiment.
3) The gold foil experiment provided evidence for the nuclear model of the atom with a small, dense nucleus surrounded by electrons.
This document provides a historical overview of atomic models from ancient Greek philosophers to modern scientific theories. It summarizes key developments including:
- Democritus' idea in the 5th century BC that matter is made of indivisible atoms in empty space.
- John Dalton's atomic theory from 1800 which proposed that all matter is made of atoms that combine in simple whole number ratios.
- J.J. Thomson's "plum pudding" model from 1900 which incorporated Ernest Rutherford's discovery of the nucleus through alpha particle scattering experiments.
- Niels Bohr's 1913 model where electrons orbit the nucleus in defined shells, accounting for atomic spectra.
- Discovery of neutrons, isot
This document outlines the key concepts to be covered in a Year 11 100 Science course on aspects of acids and bases, including atomic structure, properties of acids and bases, rates of reaction and particle theory, uses of acids and bases, and restrictions on the acids and bases included in the course. Students will study electron configuration, ionic bonding, naming ionic compounds, properties of acids and bases such as releasing hydrogen ions in water and reacting to form salts, and the rates of reactions and particle theory explanations. Assessment will include selected aspects of acids and bases such as atomic structure, properties, uses, and rates of reaction.
This document provides a historical overview of atomic models from ancient Greek philosophers to the early 20th century discoveries. It summarizes key developments including:
- Democritus' idea that matter is made of indivisible atoms in the 5th century BC. Aristotle modified earlier theories of four elements.
- In 1800, John Dalton proposed atoms of each element are identical and atoms of different elements combine in fixed ratios, accounting for laws of conservation of mass and constant composition.
- In the early 20th century, Ernest Rutherford's gold foil experiment showed atoms are mostly empty space with a dense positive nucleus. Niels Bohr incorporated electrons orbiting the nucleus in fixed shells to explain emission spectra.
The document discusses the periodic classification of elements. It describes early attempts at classification including grouping elements as metals and non-metals. Dobereiner classified elements into triads based on atomic mass. Newlands arranged elements in order of increasing atomic mass in octaves but this classification had defects. Mendeleev arranged elements in order of atomic mass and predicted properties of undiscovered elements, establishing the basis of the modern periodic table. The modern periodic table arranges elements by atomic number and groups elements with similar properties and valence electrons.
The document reviews atomic theory, subatomic particles, Bohr models, the electron cloud model of the atom, isotopes, electron configurations, radioactivity including half-life calculations, and percent abundances of elements in compounds; it provides examples of problems and concepts covered in the unit on topics like atomic structure, the periodic table, and nuclear chemistry.
This document discusses several key atomic and molecular properties including electron configurations, ionization energies, atomic and ionic radii, and electron affinity. It explains how atoms gain or lose electrons to form ions that have noble gas configurations. Cations are typically smaller than the parent atom, while anions are larger. Trends in various properties across the periodic table are also examined, such as how ionization energy generally increases moving left to right and up a group, and how atomic radius decreases with increasing nuclear charge. Diagonal relationships between elements are explained in terms of similar cation charge densities.
This document provides an introduction to bonding, including:
- How chemical bonds form via the sharing or transfer of valence electrons between atoms
- Common monoatomic ions like Na+, Ca2+, Cl-, and their charges
- How to write formulas for ionic compounds using charge balance
- Naming conventions for ionic compounds containing metals that form single ions or those with variable charges
- Introduction of polyatomic ions and how to name compounds containing them
1) Atoms are made up of protons, neutrons, and electrons. Protons and neutrons are in the nucleus, while electrons orbit the nucleus in shells.
2) Isotopes are atoms of the same element that have different numbers of neutrons, giving them different mass numbers but the same chemical properties.
3) Electrons fill the lowest available shell around the nucleus. The arrangement of electrons is shown in an element's electronic structure.
The document is a study guide covering the structure of the atom including:
1) Matter is made up of elementary particles like atoms, molecules, and ions. Atoms are the basic unit that make up elements.
2) The structure of an atom includes subatomic particles like protons, neutrons, and electrons. Protons and neutrons are located in the nucleus while electrons surround it in shells.
3) Atoms are classified by their proton number and nucleon number. The electronic configuration determines an element's properties.
4) Elements are arranged in the periodic table based on their atomic structure. This allows prediction of an element's physical and chemical properties.
1. Seminar Of Science
Structure Of An Atom
Submitted To:-
Ms. Anita
Submitted By:-
Neha Singla
Roll no:- 47
B.Ed
2.
3. 1a) Charged particles in matter :-
Atoms have three types of sub atomic particles. They are electrons,
protons and neutrons.
Electrons are negatively charged (e-), protons are positively
charged (p+) and neutrons have no charge (n).
The mass of an electron is 1/2000 the mass of a hydrogen atom. The
mass of a proton is equal to the mass of a hydrogen atom and is taken
as 1 unit. The mass of a neutron is equal to the mass of a hydrogen
atom and is and is taken as 1 unit.
b) Discovery of sub atomic particles :-
In 1900, J.J.Thomson discovered the presence of the negatively
charged particles called electrons in the atom.
In 1886, E.Goldstein discovered new radiations in gas discharge and
called them canal rays. These rays were positively charged. This later
led to the discovery of the positively charged particles called protons in
the atom.
In 1932 Chadwick discovered the presence of particles having no
charge in the atom called neutrons.
4. 2) Structure of an atom :-
a) Thomson’s model of an atom :-
According to Thomson an atom is similar to a Christmas pudding.
The pudding had positive charge and the electrons having negative
charge were like plums on the pudding.
He proposed that :-
i) An atom consists of a positively charged sphere and the electrons are
embedded in it.
ii) The negative and positive charges are equal in magnitude So the
atom as a whole is electrically neutral.
5. b) Rutherford’s model of an atom :-
Rutherford’s alpha scattering experiment :-
Rutherford allowed a beam of fast moving alpha particles ( α –
particles) having positive charge to fall on a thin gold foil. He observed
that :-
i) Most of the α – particles passed straight through the gold foil.
ii) Some of the α – particles were slightly deflected by small angles.
iii) Very few α – particles appeared to rebound.
6. Conclusions from Rutherford’s alpha scattering
experiment :-
i) Most of the space inside an atom is empty. (because most of the α
–
particles passed straight through the gold foil.)
ii) The atom had a small nucleus having positive charge. ( because
some of the α – particles having positive charge were slightly
deflected by small angles.)
iii) The size of the nucleus is very small compared to the size of the
atom. (because very few α – particles appeared to rebound and
most of the positive charge and mass of the atom is in the nucleus.)
Rutherford’s model of an atom :-
i) An atom has a positively charged nucleus at its centre and most of
the mass of the atom is in the nucleus.
ii) The electrons revolve around the nucleus in different orbits.
iii) The size of the nucleus is very small compared to the size of the
atom.
7. Defects of Rutherford’s model of the atom :-
Any particle in a circular orbit would undergo acceleration
and during acceleration the charged particle would radiate
energy. So the revolving electrons would lose energy and
fall into the nucleus and the atom would be unstable. We
know that atoms are stable.
Rutherford’s model
of an atom
Negatively charged
electron
- -
Negatively charged
electrons in orbits
around the nucleus
+
-
Very small positively Positively charged
charged nucleus nucleus
8. c) Bohr’s model of an atom :-
i) An atom has a positively charged nucleus at its centre and most of
the mass of the atom is in the nucleus.
ii) The electrons revolve around the nucleus in special orbits called
discrete orbits.
iii) These orbits are called shells or energy levels and are represented
by the letters K, L, M, N etc. or numbered as 1, 2, 3, 4, etc.
iv) While revolving in the discrete orbits the electrons do not radiate
energy. Shells or energy levels in an atom
9. 3) Distribution of electrons in different shells :-
The distribution of electrons in the different shells was
suggested by Bhor and Bury. The following are the rules for
filling electrons in the different shells.
i) The maximum number of electrons in a shell is given by
the formula 2n2 where n is the number of the shell 1, 2, 3
etc.
First shell or K shell can have = 2n2 = 2 x 12 = 2x1x1 = 2 electrons
Second shell or L shell can have = 2n2 = 2 x 22 = 2x2x2 = 8 electrons
Third shell or M shell can have = 2n2 = 2 x 32 = 2x3x3 = 18 electrons
Fourth shell or N shell can have = 2n2 = 2 x 42 = 2x4x4 = 32 electrons
and so on.
ii) The maximum number of electrons that can be filled in
the outermost shell is 8.
iii) Electrons cannot be filled in a shell unless the inner
shells are filled.
10. Composition of the atoms of the first eighteen elements :-
Name of Symbol Atomic Number of Number of Number of Distribution Valency
element Number Protons Neutrons Electrons Of Electrons
K L M N
Hydrogen H 1 1 - 1 1 - - - 1
Helium He 2 2 2 2 2 - - - 0
Lithium Li 3 3 4 3 2 1 - - 1
Beryllium Be 4 4 5 4 2 2 - - 2
Boron B 5 5 6 5 2 3 - - 3
Carbon C 6 6 6 6 2 4 - - 4
Nitrogen N 7 7 7 7 2 5 - - 3
Oxygen O 8 8 8 8 2 6 - - 2
Fluorine F 9 9 10 9 2 7 - - 1
Neon Ne 10 10 10 10 2 8 - - 0
Sodium Na 11 11 12 11 2 8 1 - 1
Magnesium Mg 12 12 12 12 2 8 2 - 2
Aluminium Al 13 13 14 13 2 8 3 - 3
Silicon Si 14 14 14 14 2 8 4 - 4
Phosphorus P 15 15 16 15 2 8 5 - 3,5
Sulphur S 16 16 16 16 2 8 6 - 2
Chlorine Cl 17 17 18 17 2 8 7 - 1
11. Atomic structure of the first eighteen elements :-
H He
Li Be B C N O F Ne
Na Mg Al Si P S Cl Ar
12. 5) Atomic number and Mass number :-
a) Atomic number (Z) :-
The atomic number of an element is the number of protons present in the
nucleus of the atom of the element.
All the atoms of an element have the same atomic number.
Eg :- Hydrogen – Atomic number = 1 (1 proton)
Helium - Atomic number = 2 (2 protons)
Lithium - Atomic number = 3 (3 protons)
b) Mass number (A) :-
The mass number of an element is the sum of the number of protons and
neutrons (nucleons) present in the nucleus of an atom of the element.
The mass of an atom is mainly the mass of the protons and neutrons in the
nucleus of the atom.
Eg :- Carbon – Mass number = 12 (6 protons + 6 neutrons) Mass = 12u
Aluminium – Mass number = 27 (13 protons + 14 neutrons) Mass = 27u
Sulphur – Mass number = 32 (16 protons + 16 neutrons) Mass = 32u
In the notation of an atom the Mass number
Symbol of 14
atomic number and mass number element Eg :- 7 N
are written as :- Atomic number