By simply counting the number of valence electrons present on the central atom and its neighbors, Lewis structures can be written in just three easy steps.

1. Consider the valence electrons of all participating atoms; add an electron for each negative charge and subtract one electron for each positive charge.
2. Identify the central atom and write the symbols of the atoms around central atom. In majority of polyatomic molecules, the least electronegative one will be the central atom with an exception of hydrides, for example, H₂O, NH₃ or H₂S.
3. Distribute the electron pairs throughout the molecule to satisfy the octet of all atoms present in the molecule starting from the most electronegative one. Each pair of singly bonded atoms requires one pair of electrons.
4. Each bonding pair should be represented by a single bond and the net charge is assumed to be possessed by the ion (cation or anion) as a whole and not by an individual atom.