1. 1. Good evening my name is Ashish Raj and i am here before you to show my presentation
2. 2. Content 1. What is an atom ? 2. Characteristics of atoms. 3. Different Atomic Species 4. Electrons 5. Protons 6. Neutrons 7. Thomsons model of atom. 8. Rutherfords model of atom. 9. Bohrs model of atom.
3. 3. What is an atom ? The atom is the smallest unit that defines the chemical elements and their isotopes. Most matter on Earth is made up of atoms. The size of atoms is measured in picometers (trillionths of a meter).
4. 4. Characteristics of atoms The atomic number of a chemical element (also known as its proton number) is the number of protons found in the nucleus of an atom of that element, and therefore identical to the charge number of the nucleus. It is represented by the symbol Z. 2. Mass number The mass number (A), also called atomic mass number or nucleon number, it is the total number of protons and neutrons (together known as nucleons) in an atomic nucleus. 1. Atomic number
5. 5. Different Atomic Species 1. Isotopes 2. Isobars 3. Isotones
6. 6. 1.Isotopes The term isotope is formed from the Greek roots isotopes meaning "the same place". Thus, different isotopes of a single element occupy the same position on the periodic table.
7. 7. 2. Isobar Isobars are atoms (nuclides) of different chemical elements that have the same number of nucleons. Correspondingly, isobars differ in atomic number (or number of protons) but have the same mass number.
8. 8. 3. Isotone Two nuclides are isotones if they have the very same neutron number N, but different proton number Z. For example, boron-12 and carbon- 13 nuclei both contain 7 neutrons, and so are isotones.
9. 9. Electrons The electron is a subatomic particle, symbol e with a negative elementary electric charge. And are generally thought to be elementary particles because they have no known components or substructure . And the electrons were discovered by sir J.J .Thomson
10. 10. The proton is a subatomic particle, symbol p or p+, with a positive electric charge of +1e elementary charge and mass slightly less than that of a neutron. Protons
11. 11. The neutron is a subatomic particle, symbol n .with no electric charge and a mass slightly larger than that of a proton. Protons and neutrons, each with mass approximately one atomic mass unit, constitute the nucleus of an atom, and they are collectively referred to as "nucleons". Neutron
12. 12. Thomson atomic model, earliest theoretical description of the inner structure of atoms, proposed about 1900 by Lord Kelvin and strongly supported by Sir Joseph John Thomson, who had discovered (1897) the electron, a negatively charged part of every atom. Thomsons model of atom
13. 13. The Rutherford model is a model of the atom devised by Ernest Rutherford. Rutherford directed the famous Geiger Marsden experiment in 1909 which suggested, upon Rutherford's 1911 analysis, that the so-called "plum pudding model" of J. J. Thomson of the atom was incorrect. RUTHER FORDS MODEL OF ATOM
14. 14. The model introduced by Bohr in 1913, depicts the atom as a small, positively charged nucleus surrounded by electrons that travel in circular orbits around the nucleussimilar in structure to the solar system, but with attraction provided by electrostatic forces rather than gravity. Bohrs model of atom
15. 15. Ashish Raj
16. 16. Thank you