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CHEM 121 Studioby Learn4Less · UBC CHEM 121

CHEM 121 glossary

Lewis structure

A drawing of a molecule or ion that shows every valence electron: shared pairs as lines between atoms and lone pairs as dots. A good structure uses exactly the right electron total, gives each atom an octet (H a duet) where possible and keeps formal charges small.

COHH
Formaldehyde, CHX2O\ce{CH2O}: 12 valence electrons, a C=O double bond and two lone pairs on O.

Example

HX2O\ce{H2O} has 2(1)+6=82(1) + 6 = 8 valence electrons: two O–H bonds (4 e⁻) and two lone pairs on O (4 e⁻).

See alsoValence electronSkeleton structureOctet ruleFormal charge