(a) How are the following related ?
(i) Number of valence electrons of the different elements present in the same group.
(ii) Number of the shells of the elements in the same period.
(b) How do the following change ?
(i) Number of shells of the elements as we go down a group.
(ii) Number of valence electrons of elements on moving from left to right in a period.
(iii)Atomic radius in moving from left to right along a period.
(iv) Atomic size down a group.

Explanation

(a) (i) Number of valence electrons of the elements present in a group do not change.
(ii) The elements present in the same period have same number of shells.
(b) (i) The number of shells of elements in a group gradually increase downwards.
(ii) The number of valence electrons of the elements in moving from left to right along a period gradually increase
(iii) Atomic radius decreases from left to the right.
(iv) Atomic size increases down a group.