In terms of Bohr radius a0, the radius of the second Bohr orbit of hydrogen atom is given by
4 a0
8 a0
√2 a0
2 a0
The Bohr model of atoms
Assumes that the angular momentum of electrons is quantized
Uses Einstein’s photoelectric equation
Predict continuous emission spectra for atoms
Predicts the same emission spectra for all types of atoms
The ionization energy of Hydrogen atom is 13.6 eV, the ionization energy of Helium atom would be
13.6 eV
27. 2 eV
6.8 eV
54. 4 eV
The manifestation of band structure in solids is due to
Heisenberg’s uncertainty principle
Pauli’s exclusion principle
Bohr’s correspondence principle
Boltzmann’s law
An α-particle of energy 5 MeV is scattered through 180o by a fixed uranium nucleus. The distance of the closest approach is of the order of
1 Å
10-10 cm
10-12 cm
10-15 cm
The total energy of electron in the ground state of hydrogen atom is -13.6 eV. The kinetic energy of an electron in the first excited state is
3.4 eV
1.7 eV
If the electron in a hydrogen atom jumps from an orbit with level n2 = 3 to an orbit with level n1 = 2, the emitted radiation has a wavelength given by
λ = 6/R
λ = R/6
The valence electron in alkali metal is a
ƒ - electron
p -electron
s -electron
d -electron
If 13.6 eV energy is required to ionize the hydrogen atom, then the energy required to remove an electron from n = 2 is
102 eV
Zero
-3.4 eV
The ionization energy of hydrogen atom is 13.6 eV. Following Bohr’s theory, the energy corresponding to a transition between 3rd and 4th orbit is
3.40 eV
1.51 eV
0.85 eV
0.66 eV
