What matters most in determining whether or not an electron can be removed from an atom: force or voltage?

It is the force that matters the most in determining whether an electron can be removed from an atom. The degree of the force is very important. If it is high then most likely, it would be difficult to remove the electron since it is more attached to the atom. However, if the force is low, then it is much easier to remove the electron.

The earths atmosphere is made up of nitrogen and oxygensolids turning into gases is called sublimation.