D. How does the radius of a positive and negative ion compare to a neutral atom? (1 point)

A positive ion has fewer electrons, and importantly, fewer electron shells (since atoms usually lose electrons until they get down to an empty outer shell.) This makes it smaller than a neutral atom of that element.

A negative ion has more electrons, and importantly, greater electron-electron repulsion in its outer shell. This makes it larger than a neutral atom of that element.