Which of the following statements is/are correct?

Options

A. The second ionization enthalpy of oxygen element is greater than that of fluorine element.
B. The third ionization enthalpy of phosphours is greater than that of aluminium.
C. The first ionization enthalpy of aluminium is slightly greater than that of gallium.
D. The second ionization enthalpy of copper is greater than that of zinc.

Answer

A, B, D

Explanation

(A) as removal of second electron takes place from half filled valence shell electron configuration of `S^(+)` i.e. `3s^(2)3p^(3)`.
(B) `I.E(III)` of `_(13)AI` is `2744 kJ mol^(-1)` where as that of `_(15)P` is `2910 kJ mol^(-1)`. This is because of higher nuclear charge in phosphours.
(C ) `I.E(I)` of `AI` is `577 kJ mol^(-1)` and that of `Ga` is `579 kJ mol^(-1)`. This may be because of their similar size i.e. `1.25 Å` in both.
(D) `_(5)B^(+) = 1s^(2)2s^(2), _(6)C^(+) =1s^(2)2s^(2)2p^(1)`, As s-sub shell electron has high penetration power than p-sub shell electron.
In addition `B^(+)` has completely filled `2s` sub shell. So `I.E(II)` of `B` is 2427 and that of `C` is `2354 kJ mol^(-1)`.