The general horizontal trend is that electron gain enthalpies become more negative (more enegry is released as an extra electron is added) from group `1A` through group `VII A` for a given period. Exceptions occur at the_________and________elements.

Options

A. `IIA`and`VA`
B. `IIA`and`VIA`
C. `IIIA`and`VA`
D. `IIA`and`IVA`

Answer

A

Explanation

Elements of group `IIA` and `VA` have relatively stable outerlectron configuration `ns^(2)` and `ns^(2)np^(6)`, respectively.