Question

How does the ionic radius of a nonmetal compare with its atomic radius?

Answer 1

Non-metal are the elements that can accept electrons,this creates a larger positive charge in the nucleus than the negative charge.
 Due to this attraction, electron cloud shrinks or come closer to nucleus as the result of opposite charge and become ion .
Hence, the atomic radius of a non-metal is generally smaller than the ionic radius of the same element.

Answer 2

The other user is correct