Question

The species having largest size is:

• A. Na
• B. $N{a}^{+}$
• C. K
• D. $K^{+}$

Answer 1

Answer: (C)

K

As we go down the group, the atomic radius increases - this is because of the addition of new energy shell

So, now you can think why K atom have a bigger radius than Na by yourself.

Thus, K is the largest species.