Chemical bonds are attraction between atoms which allows the formation of chemical substances that contain two or more atoms or molecules. This bond is due to the electrostatic of attraction between opposite charges, i.e. between electrons and nucleus, or as the result of a dipole (opposite charges separated by a finite distance).
Strengths of chemical bonds vary considerably. These can broadly classified into two types:
1.) Strong bonds such as covalent or ionic bonds
2.) Weak bonds such as dipole-dipole interactions, the force of London dispersion and hydrogen bonds Since opposite charges are attracted by a simple electromagnetic force
Example: The negatively charged particles (electrons) that are orbiting around the nucleus and the positively charged particles (protons) inside the nucleus attract each other. An electron which is between two nuclei will be attracted to both of them and also the nuclei will be attracted toward electrons. This attraction results in formation of a chemical bond. Due to smaller mass of electrons, they must occupy a much smaller amount of volume compared with the nucleus, and thus volume occupied by the electrons keeps the atomic nuclei competitively far apart, when compared with the size of the nuclei themselves. Thus this limits the distance between nuclei and atoms in a chemical bond.
In general, strong chemical bonding is formed by the sharing or transfer of electrons between the participating atoms. The atoms in molecules, metals, gases and most of the environment around us are held together by chemical bonds, which dictate the structure and the bulk properties of matter.