atomic structure and electronic configuration
- 1. NAME : PRIYUNGSHU MITRA CLASS : IX B ROLL NO : 25 PROJECT : CHEMISTRY
- 3. AT0MIC STRUCTURE An atom is the smallest constituent unit of ordinary matter that constitutes a chemical element. THE CONCEPT OF ATOM WAS ORIGINTED FROM TWO GREEK PHILOSOPHERS DEMOCRITUS :The theory of Democritus held that everything is composed of "atoms", which are physically, but not geometrically, indivisible; that between atoms, there lies empty space. DALTON :Dalton's atomic theory proposed that all matter was composed of atoms, indivisible and indestructible building blocks. While all atoms of an element were identical, different elements had atoms of differing size and mass.
- 4. POSTULATES OF DALTON ATOMIC THEORY :
- 6. CONCLUSIONS J.J. THOMPSONS (electrons) GOLDSTEIN (protons) LORD RUTHERFORD (atomic nucleus) JAMES CHADWICK (neutrons) ●cathode rays consists of nrgatively charged particles called electrons. ●Atoms of all types contain the same particle electrons and irrespective of how electrons are emitted,they are all-identical. ●Positive rays consists of – positively charged particles which led to the discovery of protons. ●Mass of an proton-1837 * 1.67*10-19 coloumbs ●The atom is mostly empty space, with nearly all of its mass concentrated in a tiny central nucleus. The nucleus is positively charged and surrounded at a great distance by the negatively charged electrons ●In the nucleus of the atom are present particles which possess no charge but have the mass almost equal to that of protons. ●This confirmed that the existence of neutron found to be heavy as the CONCLUSIONS OF THE FOUR SCIENTISTS
- 7. DEFLECTION OF CATHODE RAYS DISCOVERING OF ATOMIC NUCLEUS DISCOVERY OF NEUTRONS
- 8. ELECTRONS : The electron is a subatomic particle, symbol e⁻ or β⁻ , whose electric charge is negative one elementary charge. ELECTRONIC CONFIGURATION : In atomic physics and quantum chemistry, the electron configuration is the distribution of electrons of an atom or molecule in atomic or molecular orbitals. EXAMPLE OF ELECTRONIC CONFIGURATION BY SODIUM AS AN EXAMPLE
- 9. ELCTRONIC CONFIGURATION AND ATOMIC STRUCTURE OF FIRST 20 ELEMENTS
- 10. ISOTOPES : Isotopes are variants of a particular chemical element which differ in neutron number, and consequently in nucleon number. All isotopes of a given element have the same number of protons but different numbers of neutrons in each atom. PROPERETIES OF ISOTOPES : An isotope is one of two or more forms of the same chemical element. Different isotopes of an element have the same number of protons in the nucleus, giving them the same atomic number, but a different number of neutrons giving each elemental isotope a different atomic weight. EXAMPLES:hydrogen (three-1 1H, 1 2H, 1 3H) Carbon (two-6 12C, 6 13C, 6 14C)
- 11. OCTET RULE : The octet rule is a chemical rule of thumb that reflects the observation that main group elements tend to bond in such a way that each atom has eight electrons in its valence shell, giving it the same electronic configuration as a noble gas. Example : In a chemical formula, the octet rule strongly governs the number of atoms for each element in a molecule; for example, calcium fluoride is CaF2 because two fluorine atoms and one calcium satisfy the rule.
- 12. THANK YOU