ICSE Class 10 Answered

A diatomic compound is formed by the transfer of one or more electrons from the atom of a highly electropositive metallic element to an atom of a highly electronegative non-metallic element. The type of the bond formed is called as ionic or electrovalent bond. 

 

Example:

An atom of a highly electropositive metallic element such as Na loses electrons to attain the stable electronic configuration and becomes a cation. 

      Na                Na+ 

  2, 8, 1                                 2, 8 

  (Neutral)                           (Cation) 

 

An atom of a highly electronegative non-metallic element such as Cl gains electrons to attain the stable electronic configuration and becomes an anion. 

   Cl              Cl- 

 2, 8, 7                         2, 8, 8 

(Neutral)                       (Anion) 

 

Cations and anions are oppositely charged particles which attract one another to form an electrovalent bond leading to the formation of an electrovalent compound which is diatomic. 

Na⁺ + Cl⁻→  NaCl