Hi Natasha,

1. How can you tell how many bonds a transition metal will make?

Generally speaking, it's harder to predict how many bonds a transition metal will make (I would say it's pretty low yield). However, in chemistry, we have something called an 18 electron rule.

It's basically an expansion of an octet rule, but essentially metal complexes will form bonds such that they have a full set of 18 electrons, analogous to covalently bonded molecules trying to get each atom to have a full octet.

For example, Fe2+ has 6 e-, and so often forms bonds with 6 species (12 e-) for a total of 18 electrons.

However, I would say this is more advanced than the MCAT should go.

2. Are all chemical reactions (other than phase changes or decomposition reactions) lewis acid/base reactions?

Lewis acid/base reaction are incredibly general, and should apply to almost any type of reaction on the MCAT. The only exception I can think of off the top of my head are Diels Alder reactions, and this type of reaction is generally beyond the scope of the MCAT.

Whenever you can define a nucleophile and an electrophile, you have a lewis acid/base reaction going on.

Please let me know if you need further elaboration.

Katt