Physics

# Describe Applications of Electronegativity

Applications of electronegativity

(1) Nature of bond

The concept of electronegativity can be used to predict whether the bond between similar or dissimilar atoms is the non-polar covalent bond, polar covalent bond (or) ionic bond.

i) When XA = XB, i.e. XA – XB = 0, then A-B bond is non-polar covalent bond or simply covalent bond and is represented as A-B. eg. H-H bond in H2 molecule is a covalent bond and is represented as H-H bond.

ii) When XA is slightly greater than XB; (XA – XB) is small, the A-B bond is polar covalent bond and is represented as Aδ- – Bδ+ g. The O-H bonds in H2O molecule are polar covalent bonds and are represented as Oδ- – Hδ+, since XO > XH and XO – XH is small.

iii) When XA > XB, i.e., XA – XB is very large, A-B bond is more ionic or polar bond and is represented as A -B+, Since XA >> XB. For example, Na-Cl bond in Na Cl molecule is an ionic bond and is represented as Na+ Cl(Here Cl = A and Na = B).

(2) Percentage of ionic character in a polar covalent bond

Pauling estimated the percentage of ionic character in various Aδ- – Bδ+ polar covalent bonds from known (XA–XB) values and has derived the following conclusions :

(i) When (XA–XB) = 1.7, the amount of ionic character in Aδ- – Bδ+ bond is 50% and that of covalent character is also 50%. Thus A-B bond is 50% ionic and 50% covalent.

(ii) When (XA–XB) < 1.7, the amount of ionic character in Aδ- – Bδ+ bond is less than 50% and that of covalent character is more than 50%. Thus Aδ- – Bδ+ bond is predominantly covalent and hence is represented as A–B.