Electronic configuration of Ions

• Positive ions are formed when atoms loose electrons.

• Ions with single positive charge are formed when an atom loose one electron.

E.g.: - Sodium atom (Na) loose one electron to form sodium ion (Na+)

• Ions with two positive charges are formed when an atom loose two electrons.

E.g.: - Beryllium atoms (Be) loose 2 electrons to form beryllium ion (Be²).

• Therefore the number of positive charges carried by an ion depends of the number of electrons lost by a particular atoms.

• Negative ions are formed when atoms gain electrons.

• Ions with single negative charge are formed when an atom gains one electrons

E.g.: - Chlorine (Cl) atom gains one electron to form chloride ion (Cl−).

• Ions with 2 negative charges are formed when an atom gains 2 electrons.

E.g.: - Oxygen (O) atom gain 2 electrons to form oxide ion (O²−).

• Therefore the number of negative charges carried by an ion depends on the number of electrons gained by a particular atom.