Question

An element p with atomic number 20 reacts with and element Q with atomic number 17 to form a compound. answer the following question giving reasons: write the position of P and Q in the modern periodic table and the molecular formula of the compound formed when P reacts with Q.

Answer 1

Explanation:

An element whose atomic number is 20 is calcium. Whereas element whose atomic number is 17 is chlorine.

Calcium is placed in period 4 and group 2. On the other hand, chlorine is placed in period 3 and group 7.

Therefore, element P is calcium and element Q is chlorine.

The compound formed when P reacts with Q is $CaCl_{2}$. The chemical reaction is as follows.

      $Ca + Cl_{2} \rightarrow CaCl_{2}$

Answer 2

CaCl2 should be the correct answer