The Law of conservation of charge states that the net charge of an isolated system remains constant.
If a system starts out with an equal number of positive and negative charges, therešs nothing we can do to create an excess of one kind of charge in that system unless we bring in charge from outside the system (or remove some charge from the system). Likewise, if something starts out with a certain net charge, say +100 e, it will always have +100 e unless it is allowed to interact with something external to it.
Charge can be created and destroyed, but only in positive-negative pairs.
Table of elementary particle masses and charges:
Information provided by: http://physics.bu.edu