Question

An element has successive ionization enthalpies as $1^{st}$ (940), 2080, 3090, 4140, 7030, 7870, 16000 and 19500 kJ $mo{l}^{-1}$^. To which group of the periodic table does this element belong?

• A. 14
• B. 15
• C. 16
• D. 17

Answer 1

The correct option is C 16

Notice that there is an abnormal jump in the $7^{th}$ ionization enthalpy.

Therefore, the element has 6 valence electrons and hence it belongs to group 16.

The electronic configuration would be 1s²2s²2p⁶3s²3p⁴

Nevertheless, there is a big jump in the $5^{th}$ ionization enthalpy. It is due to removal of four electrons from the p-subshell, the $5^{th}$ electron has to be removed from 3s-orbital.

In general, we can say that when there is a change in the sub-shell or change in the shell, there will be a significant leap in the ionization enthalpy. There are some exceptions though.