Class 10 Science


Formation of Ionic Compounds

These notes are based on the chapter metals and non-metals from class 10 science NCERT book and CBSE syllabus.

Formation of Magnesium Chloride (MgCl2)

The atomic number of magnesium is 12
Electronic configuration of magnesium: 2, 8, 2
Number of electrons in outermost orbit = 2
Valence electron = 2

Atomic number of chlorine = 17
Electronic configuration of chlorine: 2, 8, 7
Electrons in outermost orbit = 7
Therefore, valence electrons = 7

lewis dot structure magnesium chloride

Magnesium loses two electrons in order to obtain stable electronic configuration. Each of the two chlorine atoms gains one electron lost by magnesium to obtain stable electronic configuration. The bonds so formed between magnesium and chlorine are ionic bonds and compound (magnesium chloride) is an ionic compound.

Formation of calcium chloride: (CaCl2)

Atomic number of calcium is 20.
Electronic configuration of calcium: 2, 8, 8, 2
Number of electrons in outermost orbit = 2
Valence electron = 2
Valence electrons of chlorine = 7

Calcium loses two electrons in order to achieve stable electronic configuration. Each of the two chlorine atoms on the other hand gains one electron losing from calcium to get stability. By losing of two electrons calcium gets two positive charges over it. Each of the chlorine atoms gets one positive charge over it.

lewis dot structure calcium chloride

The bonds formed in the calcium chloride are ionic bonds and compound (calcium chloride) is an ionic compound. In similar way, Barium chloride is formed.

Formation of Calcium oxide (CaO)

Valence electron = 2
Atomic number of oxygen is 8
Electronic configuration of oxygen is: 2, 6
Number of electrons in outermost orbit = 6
Valence electron = 6

Calcium loses two electrons and gets two positive charges over it in order to get stability. Oxygen gains two electrons, lost by calcium and thus gets two negative charges over it.

lewis dot structure calcium oxide

Bond formed between calcium oxide is ionic bond. Calcium oxide is an ionic compound. In similar way, magnesium oxide is formed.

Properties of Ionic compound