Question

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

• A. $Z_{eff}$for an electron is a 2s orbital is the same as $Z_{eff}$ for an electron is a 2p orbital.
• B. An electron is the 2s orbital has the same energy as an electron is the 2p orbital.
• C. $Z_{eff}$ for an electron is 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 1

Answer: (D)

The two electrons present in the 2s orbital have spin quantum numbers, $m_{s}$ but of opposite sign.

Answer 2

: (1) $Z_{eff}$ for an electron in a 2s orbital is greater than that in a 2p orbital (s orbital is more tightly bound to nucleus than p orbital).

(2) Energy of 2s < 2p, lower the value of n + l, lower is the energy.

(3) $Z_{eff}$ for an electron in 1 s orbital is greater than $Z_{eff}$ for an electron in a 2s orbital.

(4) The two electrons present in any orbital have spin quantum numbers with opposite sign (i.e., $m_{s} = + \frac{1}{2}and - \frac{1}{2}$)