Hydrogen molecule
The formation of the hydrogen, H2, molecule can be described simplistically using the Lewis Electron-dot symbol of the H atom.
Each H atom has 1 valence electron. When two H atoms react, they share a pair of electrons. In the sharing of a pair of electrons a chemical bond is formed. Because the bond involves sharing of electrons, it is called a covalent bond.
The driving force behind the formation of a H2 molecule is that in the sharing arrangement, each H atom in the H2 molecule is able to achieve a stable arrangement of a filled shell.
Since electrons in a bond are not really dots, another way to represent the hydrogen bond is by using an electron cloud diagram.
The above image is a representation of the electron cloud about the hydrogen atoms. The identical electron clouds about each hydrogen atom indicate that in the hydrogen molecule, the electrons are shared equally between the two hydrogen nuclei because both H atoms have the same electronegativity. The bond that forms between the hydrogen nuclei is said to be a nonpolar covalent bond.
