Hi Natasha,

Generally speaking, elements in the same group are most similar. When this is not applicable, you look for the elements closest by (for transition metals generally)

There is a tough question where they test this which often confuses students - in this question Rh does not represent Rhenium, Rh represents rhodium. Rhenium is Re on the periodic table, and as a result does not act similarly to Co in the way that iron does.

Please let me know if I haven't addressed your question sufficiently.

Katt