Chemistry Periodic Table Trends Question

Which ion in each pair has the smaller atomic radius ?
1) K+ or O2-
2) Ba2+ or I-
3) Al3+ or P 3-
4) K+ or Cs+
5) Fe2+ or Fe3+
6) F- or S2-

Thanks!!

* SIMPLY = when you go left to right, the radius decrease, and when you go bottom to top, the radius increase.

1) O2 it's above K and right side
2) I same reason
3) P3- because it's more to right side
4)K because it's more to up
5) fe2+ this has gain more ions ( the laerger the number of ions it has) the smaller the radius is
6)F top and right

I'm not going to go through the list, but essentially, the farther you go down the columns (groups), the larger the radius, and the further you go across a row (period), the smaller the radius. Dan, above me, is wrong because as you go across a period, there are more electrons, but they are all on the same energy level. This means that there is greater attractive force between the electrons and nucleus, so the radius will be smaller.

the trend is smaller going down, and smaller to the left on the periodic table