Why do atoms want 8 valence electrons?

Most of the atoms want 8 electrons in their outermost shell. These shells are energy levels in which electrons revolve around the nucleus.

Each energy level or shell can hold a certain amount of energy.

We will understand “why do atoms want 8 electrons” through the following points.

  1.  Valence electrons

  2.  Octet rule

  3. Energy levels

  4.  Stable electronic configuration

 

   1. Valence electrons

The electrons present in the outermost shell are called valence electrons. These electrons are responsible for the chemical behavior of an atom.

   2. Octet Rule

According to this law, every atom wants to complete eight electrons in its outermost shell, and for this the atom gain or lose or share electrons.

   3. Energy levels

 Electrons revolve in energy levels (orbitals) around the nucleus. Each energy level can hold a certain amount of energy. To maintain the energy level, electrons move in or out of the shell.

 

   4. Stable electronic configuration

The outermost shell of noble gases is fulfilled. They have 8 electrons in their outermost shell. These gases do not gain, lose or share electrons.

These gases cannot participate in any chemical reactions (in normal conditions), so they are called inert gases.

These noble gases have stable electronic configurations.

 So to achieve stable electronic configuration like noble gases, atoms of other elements want 8 electrons in their outermost shell

Why  is it different for hydrogen and helium?

Hydrogen and helium do not follow the octet rule as they have only one shell (K) that can hold a maximum of 2 electrons.

Each shell or energy level can hold a certain amount of energy.