Basic properties of electric charge:
(i) Quantization of electric charge
The fundamental unit of electric charge (e) is the charge carried by the electron and its unit is coulomb has the magnitude 1.6 x 10-19 C.
In nature, the electric charge of any system is always an integral multiple of the least amount of charge. It means that the quantity can take only one of the discrete set of values. The charge, q = ne where n is an integer.
(ii) Conservation of electric charge
Electric charges can neither be created nor destroyed. According to the law of conservation of electric charge, the total charge in an isolated system always remains constant. But the charges can be transferred from one part of the system to another, such that the total charge always remains conserved. For example, Uranium (92U238) can decay by emitting an alpha particle (2He4 nucleus) and transforming to thorium (90H234).
92U238 → 90H234 + 2He4
Total charge before decay = +92e, total charge after decay = 90e + 2e. Hence, the total charge is conserved. i.e. it remains constant.
(iii) Additive nature of charge
The total electric charge of a system is equal to the algebraic sum of electric charges located in the system. For example, if two charged bodies of charges +2q, -5q are brought in contact, the total charge of the system is -3q.