Question

Which of the following elements would have the largest atomic radius?

• A. $Cl$
• B. $F$
• C. $Li$
• D. $Ne$
• E. $Na$

Answer 1

The correct option is E $Na$

Option E is the correct answer.

We know that down a group in the periodic table, as atomic number increases, the number of shells increases and hence atomic radius also increases. Along a period, as atomic number increases, the nuclear charge also increases and hence the nuclear force of attraction increases too. Thus, atomic radius decreases along a period. Among the above-mentioned elements, $Li$ and $F$ and $Ne$ belong to the second period. Whereas, $Na$ and $Cl$ belong to the third period.

The third period will have larger atomic radius than the second period since the third period lies below the second period. Moreover, $Na$ lies to the left of the periodic table and $Cl$ lies to the right of the periodic table. Hence $Na$ has the largest atomic radius of the above-mentioned elements.