(a) How are the following related?
(i) Number of valence electrons of different elements in the same group.
(ii) Number of shells of elements in the same period.
(b) How do the following change?
(i) Number of shells of 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.
(a) (i) Different elements in same group have same number of valence electrons.
(ii) Number of shells of elements in same period are equal.
(b) (i) Number of shells of elements goes on increasing down the group.
(ii) Number of valence electrons of elements goes on increasing on moving from left to right in a period, e.g. lithium has 1, beryllium has 2, boron has 3, carbon has 4, nitrogen has 5, oxygen has 6, fluorine has 7 and neon has 8 valence electrons.
(iii) Atomic radius goes on decreasing in moving from left to right along a period.
(iv) Atomic size goes on increasing down a group.