An atom has eight protons.
Since each proton has a charge of +1, the whole atom
so far has a charge of +8 .
If we want an overall charge of only +2, we need to cancel
or neutralize 6 of those positive charges somehow.
We have two choices:
==> rip off 6 protons and throw them away
Well, the protons are in the nucleus. It's almost impossible to
rip particles out of a nucleus, and if you manage to do it, you
end up with a completely different substance. So the first choice
doesn't seem like the way to go. Let's look at the second one.
==> glue something onto the atom that has 6 negative charges
NOW we're getting somewhere !
ELECTRONS have negative charges ... 1 apiece.
Electrons are everywhere, they're easy to get, and easy to
work with. We could go on Amazon and order 6 electrons,
we could have them by tomorrow, and GET THIS: Opposite
charges attract each other anyway, so if we bring the electrons
anywhere near the 8 protons, they'll snap in and get glued on
automatically. THIS is the way to change our atom to +2 ...
with some electrons.