Question

Lanthanoid contraction is caused due to 

a. the same effective nuclear charge from Ce to Lu 

b. the imperfect sheiding on outer electrons by 4f electrons from the nuclear charge 

c. the appreciable shielding on outer by 4f electrons from the nuclear charge 

d. the appreciable shielding on outer electrons by 5d electrons from the nuclear charge.

Answer 1

b. the imperfect sheiding on outer electrons by 4f electrons from the nuclear charge