Given below are two statements: In the light of the above statements, choose the most appropriate answer from the options given below :
- Statement I is incorrect but Statement II is correct
- Statement I is correct but Statement II is incorrect
- Both Statement I and Statement II are correct
- Both Statement I and Statement II are incorrect
Answer
(2) Statement I is correct but Statement II is incorrect
Solution
Statement I: poor shielding by d and f electrons ⇒ ns2 pair reluctant to bond (inert pair effect), stronger down the group
⇒ +1 state more stable down the group (Tl: +1 > +3) ⇒ Statement I is correct
Statement II: atomic radius Al = 143 pm, Ga = 135 pm
∵ Ga has 10 extra 3d electrons that shield poorly ⇒ higher effective nuclear charge ⇒ Ga < Al ⇒ Statement II is incorrect
Answer: (2)