Positive and negative charges of different atoms behave like poles of a magnet.When two atoms with the same charge come close,they repel each other.On the other hand,two atoms with different charges attract each other.Normally,all atoms have an equal number of electrons and protons.therefore,the net charge on an atom is zero and the atom is said to be neutral.In other words,naturally,objects have no net charge on them.In some materials,atoms have free-moving electrons.When these electrons move from one object to another,it results in the formation of electrically charged objects,which cause the production of electricity.