Re: HOW and WHY does Calcium form a Ca2+ ion

Matt,

I'm not entirely sure what your difficulty is. Even isolated Ca atoms can form 
Ca++ and 2 electrons, if enough energy is pumped in; but normally calcium metal 
reacts with something that likes to soak up the electrons that calcium loses. 
We can justify the formation of Ca++ by noticing that, when Ca loses two 
electrons, its electron configuration is the same as that of Ar.

That wouldn't be enough to make loss of the two electrons favorable by itself, 
of course, but when you combine that with the energy released when the 
electrons are absorbed by, say, an oxygen atom, you get a net energy gain.

I hope I've answered your question!

Dan Berger