Question

elements A,B,C have atomic number 9,20,10 respectively
a)state which one is:i)a non metal ii)a metal iii) chemically inert

b)write down the formula of the compound formed by two of the above element

Answer 1

A is nonmetal
B is a Metal
C is chemically inert

Answer 2

(a)

i)a non metal is A because a has electronic configuration 2,7 and it will accept one .

ii) a metal is B because its electronic configuration is

2,8,8,2 and it will give the two electrons in its valance cell.

iii) chemically inert-C because it's atomic number is 10 and configuration would be 2,8 so it has completed its outermost (valence) cell

(b) A and B will only react as they are not chemically inert

so the formula would be

A2B

hope it helps!