Basics

• diatomic molecules are made up of only two atoms

  
• There are 7 diatomic elements in the periodic table:

  H2, N2, O2, F2, Cl2, Br2, I2
• atoms for bonds in order to achieve the most stable out electron arrangement - a full outer shell
• Covalent Bond - two positive nuclei held together by their common attraction for shared pair of electrons