Test: Bohrs Model of Atom (April 28) - NEET MCQ

Because isotones means the same number of neutron, So, from the question, option c is right, number of neutron in k is,39-19= 20,and,the number of neutron in ca is also 40-20=20 so it is isotones. 

The potential energy of an electron in the first Bohr’s orbit in the H-atom is

This energy is defined as an atomic unit of energy called HARTREE.

Therefore, electronic transition (a) requires greatest quantity of energy.

E₁ = Energy of H-atom in the ground state = 13.6 eV 

Energy absorbed = (13.6 x 1.5) = 20.4 eV
E₂ = Energy of the excited state
= 13.6+ 20.4= 34.0 eV
ΔE = KE = (E₂ - E₁)
= 34.0 - 13.6 = 20.4 eV

Ionisation energy = - Energy of the electron

Also, angular momentum is quantised

For H - atom , Z = 1

For the spectral line in H -atom and H -like species (one electron)

For Lyman series
For shortest wavelength (maximum wave number) n₂ → ∞



For longest wave length (minimum wave number), n₂ = (n₁, + 1).
For Balmer series, n₁ = 2