# As a neutral sulfur atom gains two electrons, what happens to the radius of the atom?

Why...well we begin with the sulfur atom, $Z = 16$...now particle size is a function of nuclear charge, $Z$, and SHIELDING by other electrons.. We would expect shielding to win in this given that we have reduced the sulfur atom to give ${S}^{2 -}$...
But as chemists, as physical scientists, we should take a good, hard, long at the data... This site tells us that the size of the sulfur atom is $100 \times {10}^{-} 12 \cdot m$, and that of the sulfide ion is ???