Question

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

(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 the2p 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 number $m_s$ but of opposite sign

Answer 1

(a) Electrons in 2s and 2p orbitals have different screen effect. Hence, their $Z_{eff}$ is different. $Z_{eff}$ of 2s orbital > $Z_{eff}$ of 2p orbital

(b) Energy of 2s obital < enrgy of 2p orbital

(c) $Z_{eff}$ of 1s orbital $\ne Z_{eff}$ of 2s orbital

Hence, it is incorrect

(d) For the two electrons of 2s orbital, the value of $m_s$ is $+\frac{1}{2}and-\frac{1}{2}$

Hence, it is correct.