Question

Which of the following indicates the correct order of variation in atomic size?

• A. $Be>C>F>Ne$
• B. $Be>C>F<Ne$
• C. $Be<C<F<Ne$
• D. $F<Ne<Be<C$

Answer 1

The correct option is B $Be>C>F<Ne$

The size of an element within a period decreases from left to right up to halogens because of the net increase in nuclear charge on the outermost electron. From halogen to noble gases the size increases as the last electron completes the octet and compensates for the increase in nuclear charge. Therefore among $B,C,F,Ne$, the size will follow the order:

$B>C>F<Ne$

Option $B$ is correct.