Examine the statement.  an atom has eight protons.  what would need to happen for the atom to have an overall charge of +2?  

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.