Final answer:
The basic procedure for writing a covalent Lewis structure involves determining the total number of valence electrons, drawing a skeleton structure, distributing lone pairs, and forming multiple bonds if necessary.
Step-by-step explanation:
- Determine the total number of valence (outer shell) electrons. For cations, subtract one electron for each positive charge. For anions, add one electron for each negative charge.
- Draw a skeleton structure of the molecule or ion, arranging the atoms around a central atom. (Generally, the least electronegative element should be placed in the center.) Connect each atom to the central atom with a single bond (one electron pair).
- Distribute the remaining electrons as lone pairs on the terminal atoms (except hydrogen), completing an octet for each atom.
- If there are still remaining electrons, move electron pairs from the terminal atoms to form multiple bonds (double or triple bonds) between atoms.