The element expected to form largest ion to achieve the nearest noble gas configuration is
- F
- N
- Na
- O
Answer
(2) N
Solution
The ions formed are N3-, O2-, F- and Na+; all are isoelectronic (10 electrons, Ne configuration).
For isoelectronic species, the smaller the nuclear charge, the larger the ion:
N3- (Z = 7) > O2- (Z = 8) > F- (Z = 9) > Na+ (Z = 11)
Hence N forms the largest ion.
Answer: (2)