What are some properties of electrical charges in chemistry?
For (i), that charge is conserved in every chemical reaction.
For (ii), that the initial assignment of positive and negative charge was entirely arbitrary.
We assign protonic, nuclear charges, as positive; and electronic charges as negative. It would have made much more sense in the days of Thomson (late 1800's) to have assigned the electronic charge as positive. This would have saved generations of quantum chemists from getting the wrong sign on their answer when they counted odd when it was even in some many electron calculation.
The point is that protons and electrons have opposite electronic charges. For both ions and neutral species, we can sum up the electronic charge versus nuclear and assign a formal charge to the atom. Lone pairs devolve solely to atom that holds them; for covalent bonds we assign one electron each to the participating atoms.