How the atom electrical charged

When the number of electrons in an atom is different than the number of protons it is electrically charged, and is called an ion. An atom becomes an ion by gaining or losing one or more electrons. There are various mechanisms that can make this happen. Salts can disassociate in certain solutions, turning from a single molecule into separate positive and negative ions. For example table salt NaCl can be disassociated in water into Na+ and Cl- ions. Ions can also be formed by subjecting the atom to radiation or to high temperatures.