Question

if the protons and electrons have a charge, why doesn't the oxygen atom have a charge?

Answer 1

What does -8+8 equal?

Answer 2

It build on the same principal.
The fundamental charge of a proton \(e\) is the negative change for an electron \(-e\).
Now the oxygen atom contain 8 protons and 8 electrons. So to calculate the net change we simply put it this way:
\[-8e+8e=0\]
You'll see that if the number of protons is higher than the number of electrons we get a positive change and vice versa for a negative change.

Answer 3

Yeah, right^ . Nice explanation @frostbite .