Atomic Structure Test - 12

The second ionisation potential of helium is the same as the first ionisation potential of He⁺,and theBohr equation may be applied to the ground state of He⁺, for which Z = 2 and n = 1. From the Z² dependence of the energy of a Bohr level, I.P. of (He⁺) = 2² x I.P. (H) = 4 x 13.6 eV = 54.4 eV.

Transition of the electron from a higher level to third level in hydrogen atom gives rise to line in Paschen series.

First line in Balmer series means transition from n = 3 to n = 2. Now, 9^th orbit of Li²⁺ has the same energy as third orbit of hydrogen atom and 6^th orbit of Li²⁺ has the same energy as second orbit of hydrogen atom. Therefore, n = 9 to n = 6 transition in Li²⁺ would have the same wavelength as first line in Balmer series of hydrogen spectrum.

Maximum e^- in a sub-shell = 2(2l + 1)
For example,
when l = 2 (for d sub-shell)
Max e^- = 2 [(2 × 2) + 1] = 10

Number of nodal planes = l,but in dz² orbital, number of nodal planes is zero due to the pressure of ring around the dz² orbital.