Write a report on the history of unveiling the structure of atom from John Dalton and niels bhor
Answers
John Dalton, an English chemist, meteorologist and physicist, began a series of experiments which made him propose the theory of atomic compositions, which are known as Dalton’s Atomic Theory. This theory is one of the cornerstones of modern physics and chemistry.
According to Dalton's Atomic Theory
1) All matter is made of atoms. Atoms are indivisible and indestructible.
2) All atoms of a given element are identical in mass and properties.
3) Compounds are formed by a combination of two or more different kinds of atoms.
4) A chemical reaction is a rearrangement of atoms.
However, the modern atomic theory is a little more involved than Dalton's theory but the essence of Dalton's theory remains valid.
The 4 postulates of Bohr's atomic model are:-
1) Electrons assume only certain orbits around the nucleus. These orbits are stable and called "stationary" orbits.
2)Each orbit has an energy associated with it. For example, the orbit closest to the nucleus has an energy E1, the next closest E2 and so on.
3)Light is emitted when an electron jumps from a higher orbit to a lower orbit and absorbed when it jumps from a lower to the higher orbit.
4) The energy and frequency of light emitted or absorbed is given by the difference between the two orbit energies, e.g, E (light) = Ef - Ein = E(light)/hh = Planck's constant = 6.627 x 10⁻³⁴ Jswhere "f" and "i" represent final and initial.
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