Question

five elements a,b,c,d,e have atomic number 11,8,18,20,17 respectively. which of them - have a valency zero
forms an anion with-2 charge?
forms an cation with +1 charge?
is a noble gas?
is a member of group vIIA?
is a member of fourth period?​

Answer 1

Explanation:

a. 18

b. 8

c. 11

d. 18

e. 17

f. 20