Bohr's first postulate
An electron in an atom exists in only certain stable, circular orbits called "Energy levels"
Bohr's second postulate
- An electron absorbs energy to jump from a lower orbit to a higher orbit
- An electron emits energy when it falls from a higher orbit to a lower orbit
Bohr's third postulate
- The only orbits (energy levels) an electron can exist are those with the angular momentum = nh/2π
- m0vrn = nh/2π
ν = c/λ
Frequency (ν) = Hz
Wavelength (λ) = m
Velocity (c) = m/s
c = 3 x 108m/s
E = E2
= h c / λ
h = Planck’s constant
= 6.626 x 10-34 Joule.sec
F = e2/4πεoεr2 N
e = electron charge, r = distance of separation (m),
εo = permittivity of free space = 8.854 x 10-12 F /m,
ε = dielectric constant of the medium.
En = -13.6 / n2 eV
rn= 0.53 n2 A
Ionization energy is....
- is the energy required by an electron to leave the atom.
- i.e. the electron in an atom should get sufficient energy to reach
The maximum number of electrons that can occupy an energy level in any atom
[where n is the order of the energy level (n=1,2,3,4,….).]
Bohr’s atom model explains the behaviour of hydrogen atom.