Identify a molecule which does not exist.
- Li2
- C2
- O2
- He2
Answer
(4) He2
Solution
Bond order = 12(Nb - Na)
Li2: 1s2 * 1s2 2s2 B.O. = 12(4 - 2) = 1
C2: B.O. = 12(8 - 4) = 2
O2: B.O. = 12(10 - 6) = 2
He2: 1s2 * 1s2 B.O. = 12(2 - 2) = 0
as per NCERT, He2 does not exist.
Answer: (4)