Question

Which one of the following is the correct order of increasing size?

• A.
• B.
• C.
• D.

Answer 1

The correct option is B

A positive ion is always smaller than a negative ion when they are isoelectronic species, so in this case ($N{a}^{+}$ is smaller than $F^{-}$ ).

Also, in a period the, size decreases from left to right and increases again at the end. So, Al would be smaller than Mg.