This section contains questions each with two columns-I and II. Match the items given in column with that in column II.

Answer

A-p; b-p,q; C-q,s D-p,q,r,s

Explanation

` A) Gd (Z=64)-[Xe] 4f^7 5d^1 6s^2` shows an oxidation state of `+ 3 (4f^7`)
B) `Tb(Z=65)= [Xe]4f^9 5d^(0) 6s^2` shows oxidation states of `+3 (4f^8) and +4 (4f^7)`.
C) Th (actinoid Z=90)=[Rn] `5f^0 6d^2 7s^2 `- shows oxidation states +4 (5`f^0`).
D) U (heaviest of all, Z=92)=[Rn]`5f^3 6d^1 7s^2` shows oxidation states `+3 (5f^3 ), +4(5f^2), +5(5f^1 ), +6(5f^0)`