Chemistry help, atomic radii

For each of the following pairs, select the one with the largest atomic radius:

(i) Sulphur atom or a Sulphide ion

(ii) Magnesium atom or a magnesium ion

(iii) Hydrogen ion, H+ or a Hydride ion, H-

S2-, Mg and H-. Always pick the one with the most electrons.

(i) S=16 = 2,8,6 & S-2 = 18 = 2,8,8
SO SULPHIDE ION IS LARGER THAN S. BECAUSE FORCE OF ATTRACTION
BETWEEN NUCLEUS & OUTERMOST ELECTRONS IN SULPHIDE ION
IS LESS. SO RADIUS LARGE.
(ii) Mg= 12= 2,8,2& Mg+2 = 2.8
Mg IS LARGER THAN MAGNISIUM ION .DUE TO THREE ORBIT.
(iii) H+= NO ELECTRON , H- = 2
H- IS LARGER THAN H+

Generally a cation is smaller than the neutral atom because the fixed nuclear charge pulls the diminished electron charge more, so i) S is smaller than S(-2) ii) Mg(+2) is smaller than Mg and iii) H+, being a naked proton, is smaller than H(-1) which is hydrogen with an extra electron.