Question

An element x atomic number17 react wuth atomuc no 20

Answer 1

Ca+Cl2-----CaCl2

here calcium have atomic no. 20 and chlorine have 17

Answer 2

Ok

So, atomic number 17 element is Chlorine (Cl)

and atomic number 20 element is Calcium (Ca)

When Calcium reacts with Chlorine, Calcium Chloride is formed.

$Ca + Cl _{2} \: \frac{ \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: }{ \: \: \: \: }> Ca Cl _{2}$