For the electrons of oxygen atom, which of the following statement is correct?

Options

A. `Z_(eff)` for an electron in a 2s orbital is the same as `Z_(eff)` for an electron in a 2p orbital.
B. An electron in the 2s orbital has the same energy as an electron in the 2p orbital.
C. `Z_(eff)` for an electron in 1s orbital is the same as `Z_(eff)` for an electron in a 2s orbital.
D. The two electrons present in the 2s orbital have spin quantum numbers, `m_(s)` but of opposite sign.

Answer

D

Explanation

(a) `Z_(eff)` for an electron in a 2s orbital is greater than that in a 2p orbital (s orbital is more tightly bound to the nucleus than p orbital).
(b) Energy of 2s lt 2p, lower the value of n + l, lower is the energy.
( c) `Z_(eff)` for an electron in 1s orbital is greater than `Z_(eff)` for an electron in a 2s orbital.
(d) The two electrons present in any orbital have spin quantum numbers with opposite sign
`(i.e.,m_(s)=+1/2 and-1/2)`.