General Concepts for Covalent Bonding and Constructing Lewis Structures for Organic Molecules

For H (shell n = 1), this equals two electrons; for the row-2 elements (n = 2), this equals eight electrons, an “octet.”

4. The specific bond numbers are determined from the fact that each covalent bond adds one additional electron to the atom’s bonding outer valence shell. Therefore, for neutral atoms which follow the octet rule: the number of covalent bonds an atom will make will be equal to the number of additional valence electrons the atom needs to complete the outer valence shell (total to equal 2 or 8 electrons).