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 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 :
The two electrons present in the $$2s$$ orbital have spin quantum numbers, $${m_s}$$ but of opposite sign.
Solution :
(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 $$2s < 2p,$$ 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 $$\left( {{\text{i}}{\text{.e}}.,\,{m_s} = + \frac{1}{2}\,\,{\text{and}}\,\, - \frac{1}{2}} \right).$$