When an ionic compound is formed, the neutral atom is changed to a cation or an anion. The formation of cations and anions depends on the following factors:
- Low ionisation potential : – If the ionisation potential of a particular atom is low, it will lose electron(s) easily, i.e., a cation is formed easily.
- High electron affinity: – If the electron affinity value is high, anion will be formed easily, i.e., a higher electron affinity value favours ionic bonding.
- Large electronegativity difference: – If the difference in the electronegativities of two elements is higher, then the transfer of electrons will be easier. Therefore, more the difference in electronegativity, more will be the ionic nature of the resulting compound.
The metals of groups 1, 2 and 13 have a tendency to lose their valence electrons. So they combine with the non-metals of Groups 15, 16 and 17, which have a tendency to gain electron(s) and form ionic bonds.
Note: – Group 1. elements are most electropositive, i.e., they are metallic in nature. Their metallic nature increases down the group, so caesium is most electropositive.
Group 17. elements are most electronegative. Fluorine is the most electronegative element. Thus, caesium fluoride CsF is the most ionic compound.
Bonds formed between metals and non-metals are ionic or electrovalent.
Why are Ionic Compounds Stable?
Ionic compounds are formed by ions but there also exists a repulsive force between ions for like charges. Since the electrostatic force of attraction between opposite charges is much higher, it makes the ionic compounds stable.
Examples of electrovalent (ionic) compounds.
- NaCl (Sodium chloride)
- MgClâ‚‚ (Magnesium chloride)
- CaO (Calcium oxide)
- KBr (Potassium Bromide)
- CaClâ‚‚ (Calcium chloride)
frequently asked questions?
- What are the conditions necessary for the formation of an electrovalent bond-
The conditions necessary for the formation of an electrovalent bond are as follows:
(1) A donor atom with an unpaired electron is present.
(2) A third atom is present that can accept the electron from the donor atom.
(3) The distance between the donor atom and the third atom in question has to be less than the sum of the van der Waals radius of the donor atom and the van der Waals radius of the third atom. - What are the conditions for formation of an Electrovalent bond and covalent bond
The conditions necessary for the formation of an electrovalent bond are:
• The electron donating group is more electronegative than the electron withdrawing group.
• The electron withdrawing group is more electronegative than the electron donating group.
• The donor is able to form a strong, stable covalent bond.
• The acceptor is able to form a weak, stable covalent bond.
• The bond between the donor and the acceptor is not stronger than