When an atom or molecule accepts or looses an electron or electrons it gets either negative charge (when electrons gained) or a positive charge (when looses electron). The negative ion is called Anion and positve ion is called the Cation. An Ion can be Atomic or Polyatomic.
Example:
Sodium when looses one electron forms a cation i.e. Na⁺
Chlorine when gains one electron forms an Anion i.e. Cl⁻
Result:
A negative ion (Anion) differ from an uncharged atom of the same element in the number of electrons. An anion contains more electrons than its corresponding Neutral Element.
