Question

Describe bohr's model of atom and explain its usefulness over rutherford model of atom

Answer 1

BOHR'S MODEL OF AN ATOM :

Neil Bohr in 1913 presented the

structure.

6) An electron moves around the nucleus in cons

orbits.

Number of orbits

in constant c

cular

Electrons are absent

between two

successive orbits

0000(+))

Electron in

circular orbits

Nucleus

h

Electrons moving around in circular orbits

(in) The electrons move around the nucleus in only those circular

orbits for which their angular momentum (mur) is an integral

multiple of . This is called the condition of quantization

nh

The angular momentum (mvr) of an electron is wherem

is the mass of electron,r is radius of its circular orbit, vis the

velocity of electron, h is Planck's constant; n is a whole

number whose value may be 1,2,3,4 etc. nis called principal

quantum number.

(iii) When energy is provided to an atom, its electrons get excited

by absorption of energy and jumps to the orbit of higher

energy.

Answer 2

• An atom holds the nucleus at the centre.
• Negatively charged electrons revolve around the nucleus.
• The atoms in it contains distinct orbits of electrons.
• Electrons do not radiate energy when they are in their orbits.
• The distinct orbits are named as K, L, M, N orbits. Numbers used to denote them are n=1, 2, 3, 4