7.2 Application of Electronegativity

  Periodic Table

• Nomenclature: Compounds formed from two nonmetals are called binary compounds. Name of more electronegative element is written at the end and ‘ide’ is suffixed to it. The name of less electronegative element is written before the name of more electronegative element of the formula.
• Nature of bond: If difference of electronegativity of the two elements is 1.7 or more, then the bond between them is ionic in nature whereas if it is less than 1.7, then covalent bond is formed. (HF is exception in which bond is covalent although the difference in electronegativity is 1.9).
• Metallic and nonmetallic nature: Generally values of electronegativity of metallic elements are low, whereas electronegativity values of nonmetals are high.
• Partial ionic character in covalent bonds: Partial ionic characters are generated in covalent compounds by the difference of electronegativity. Hanny & Smith calculated percentage of ionic character from the difference of electronegativity.

• Bond Length: When difference of electronegativity of atoms present in a molecule is increased, then bond length decreases. Bond length is represented as d_(A-B). Shoemaker and Stephensen determined the following formula,$${d_{A - B}} = {r_A} + {r_B} - 0.09({X_A} - {X_B})$$$${d_{A - B}} = \frac{1}{2}({d_{A - A}} + {d_{B - B}}) - 0.09({X_A} - {X_B})$$