Question

What is the periodic trend in the variation of valency while going down a group?Explain the answer with reference to the group 1,group 2,and group 18

Answer 1

the vacancy remain same while going down a group Valency of Li and na in group 1 is same and valency of mg and ca is same and valency of He and Ne is same

Answer 2

Answer:

1) The valency of an element is determined by the number of valence electrons in the outermost shell of an atom of an element.

2)aAl the elements in a group have the same number of valence elements. Therefore elements in the same group should have the same valency. For example, the elements of group 1 (H,Na,Li,K,etc) contain only one valence electron the valency of elements of group 1 is one. Similarly for group 2 (Be,Mg,Ca) contain two valence electrons the valency of elements of group 2 is two.

3) element of group 18 (Ne,Ar) contain 8 electrons (exception, helium contains 2 electrons). The their octet is completed their valency is zero.