posted by john .
write the formulas and give the names of the compounds formed by the following ions a) Cr^2+ and F^- b) Ni^2+ and O^2 and c) Fe^3+ and O^2-
Do you know how to do these? If not you need to learn to do them. You want to make the subscripts (which we don't write as subscripts on these boards--that is, we make them as in CrF2 in which the 2 is understood to be a subscript.) so that the charges on the two ions add to zero. For example, Cr+2 and 2F ad -1 each will give CrF2. For Ni at +2 and O and -2, NiO would be neutral. etc.