An electric charge (q or Q) is the quantity of unbalanced electricity in an object (either positive or negative). It is interpreted as an excess or deficiency of electrons. Matter that possesses a charge is influenced by and produces electromagnetic fields.
Electrons, by convention have an elementary charge of -1. Ions are either positively or negatively charged. The unit of measurement of the charge of an object is the coulomb, which represents 6.24 x 1018 elementary charges.