Ionic Bond



What is an Ionic Bond?

Ionic bond is formed when one or more valence electrons are transferred between the atoms of the element.Due to this transfer of electrons,the atoms becomes ions, and the attractive force that exists between these two ions is known as ionic bonding .


Ionic bond is the chemical bond that is formed due to the transfer of valence electrons between the two constituent atoms of the element.


Example

Let us consider a molecule of NaCl as an example of ionic bond formation. The ionic bond formation of NaCl (Sodium Chloride) can be understood by Lewis electron-dot structure.

Lewis Electron-dot Structure of NaCl

Lewis electron dot structure is based on the concept of number of valence electrons present in the outermost shell of the atom.

The element NaCl contains two atoms Na and Cl.

Na (Sodium) Atom

The electronic configuration of Na is - 1S2 2S2 2P6 3S1

By the above electronic configuration, we can observe that one valence electron is present in the outermost shell of Na atom. So the electron dot structure of Na atom can be written as

Na-dot structure

Cl (Chlorine) Atom

The electronic configuration of Cl is - 1S2 2S2 2P6 3S2 3P5

By the above electronic configuration, we can observe that 7 valence electrons are present in the outermost shell of Cl atom. So the electron dot structure of Cl atom can be written as

Na-dot structure

Formation of Ionic Bond in NaCl

The valence electron of Na (Sodium) atom is transferred to Cl (Chlorine) atom to attain stable electronic configuration (Octet configuration). The Na atom becomes Na+ cation due to donation of electron and Cl atom becomes Cl - anion due to acceptance of electron. Therefore an ionic bond is formed between Na and Cl

Na-dot structure

Characteristics of Ionic Solids

The Ionic solids possess the following characteristics...

  • Ionic solids are hard, strong and brittle.
  • Ionic solids have high melting and boiling points.
  • Ionic solids are good insulators of electricity due to low conductivity at low temperature.
  • Ionic solids possess high cohesive energy.
  • Ionic solids are soluble in polar solvents like water and insoluble in non-polar solvents like ether.