Electric charge is the physical property of matter that causes it to experience a force. It is the excess or deficiency of electrons in the valance cell or outermost orbit of an atom. There are two types of electric charges: positive and negative. If an atom has an excess of electrons in the valance cell, then it is called negatively charged (-vely charged) and an atom with deficiency of electron is called positively charged (+vely charged).
Positively charged substances are repelled from other positively charged substances, but attracted to negatively charged substances; negatively charged substances are repelled from negative and attracted to positive. The SI derived unit of electric charge is the coulomb (C), although in electrical engineering it is also common to use the ampere-hour (Ah), and in chemistry it is common to use the elementary charge (e) as a unit. The symbol Q is often used to denote charge.
An electron is an elementary particle charged with a small and constant quantity of negative electricity. A proton is similarly defined but charged with positive electricity whereas neutron is uncharged and therefore neutral. In atom, the number of electrons normally equals the number of protons; it is the number of protons that determines to which element type the atom belongs. An atom can have one or more electrons added to it or taken away. This does not change its elemental classification but it disturbs its electrical balance. A charged atom is called ion. A body containing a number of ionized atoms is said to be electrically charged. Fig. 1 shows the behavior of likely charged and unlikely charged atoms.
The behavior of likely charged and unlikely charged atoms.
The charges of electron and proton are.
qe = -1.602 × 10-19 C
qp = +1.602 × 10-19 C
