Question

Reaction of $Ca$ is faster than $Mg$ with $O_2$ because:

• A. Ionization enthalpy of $Ca$ is more than that of $Mg$
• B. Ionization enthalpy of $Mg$ is more than that of $Ca$
• C. $Ca$ has 6 isotopes
• D. $Ca$ is heavier than $Mg$

Answer 1

Answer: (B)

Ionization enthalpy of $Mg$ is more than that of $Ca$

Ca and Mg are in the same group. Ionization energy decreases along with the group. As Ca has less ionization enthalpy, it loses electron easily and thus reacts faster than Mg.

So Ionization enthalpy of $Mg$ is more than that of $Ca$ can justify the above statement.

Hence, option B is correct.