Given below are two statements : In the light of the above statements, choose the correct answer from the options given below :
- Both Statement I and Statement II are true
- Both Statement I and Statement II are false
- Statement I is true but Statement II is false
- Statement I is false but Statement II is true
Answer
(1) Both Statement I and Statement II are true
Solution
Statement I: the third valence electron is removed from the M2+ ion.
Sc2+ (3d1) attains the stable noble-gas configuration on becoming Sc3+, so its value is the lowest (2389 kJ mol-1).
In Zn2+ (3d10) the electron must be removed from a stable, completely filled d subshell, so its value is the highest (3833 kJ mol-1); Mn is 3248 and Cu 3554. Hence Statement I is true.
Statement II: o increases with the charge on the metal ion and with the field strength of the ligand (en > H2O), so the CFSE order is [Co(H2O)6]2+ < [Co(H2O)6]3+ < [Co(en)3]3+ and Statement II is true.
Answer: (1)