Predict the position of the element in the periodic table satisfying the electronic configuration

Question

(a) Predict the position of the element in the periodic table satisfying the electronic configuration (n-l)d¹ns² when n = 4. 

(b) Name the species which is isoelectronic with Cl^–, 

(c) Why are f-block elements are placed in a separate row at the bottom of periodic table?

Answer 1

(a) It belongs to group 3 and fourth period. 

(b) Ar is isoelectronic with Cl⁺.

(c) It is because they resemble each other but do not resemble any other group elements.