Question

Which one of the following atoms will have largest size?

• A. Ca
• B. Na
• C. Mg
• D. Be

Answer 1

Answer: (A)

Ca

Atomic size increased down the group and decreases in the period from left to right. If we look at the position of $Be,Mg$, and $Ca$ then it is observed that they are present in the same column which indicates $Ca$ has a larger size than $Be$ and $Mg.Ca$ is also larger in size compared to $Na$ because it has a higher number of electrons that are present farther from the nucleus.

So, calcium ($Ca$) is the largest size among given atoms.

Hence, the correct option is $\text{A}$.