For which atom is it difficult to predict the most probable ionic charge using the periodic table?

Cobalt since it has various oxidation states. Cobalt(III) for 3+, Cobalt(II) for 2+, and rarely 1+.

Ithink that the use of creativity in the sciences entails that one produce something out of nothing or from another thing. with this, i think that the he wrote down his results as four parts of the atomic theory is the manifestation of the  creativity of john dalton.

Ibelieve it's temperature! i'm not 100% sure.