Question

The ratio in which calcium and chlorine atoms combine to form 1 molecule of ${\text{CaCl}}_2$ is

• A. 1:1
• B. 1:2
• C. 1:3
• D. 1:4

Answer 1

The correct option is B

1:2

${\text{CaCl}}_2$ is an ionic compound in which the positively charged calcium ions are attracted by the surrounding negatively charged chlorine ions and the negatively charged chlorine ions are attracted by the surrounding positively charged calcium ions. Calcium and chlorine combine in the ratio similar to their valency. Calcium has valency 2 and chlorine has valency 1.
Therefore, they combine in the ratio of 1:2.