ICSE Class 7 Answered

In case of atoms, stability means attaining electronic arrangement of inert gases i.e., octet or duplet state in its outermost shell.

Atoms of Neon, Argon, Krypton, Xenon and Radon are inert gases having eight electrons in their outermost shell.

Atoms of inert gases are very stable and unreactive with 8 electrons or 2 electrons, i.e. nearest to Helium configuration in their outermost shells.

So in order to attain stable electronic configuration, atoms tend to combine chemically by redistribution of electrons in the outermost shell or valence shell.

During this redistribution of electrons, a bond or force of attraction is developed between the atoms which bind them together to form molecules. We called this bond as Chemical Bond.

Methods of Chemical Bonding

Transfer of Electrons from one atom to another –Electrovalent Bond

Sharing of electrons between two atoms –Covalent Bond

Contribution of shared pair of electrons by one of the combining atoms –Coordinate Bond