13.1.4—Interpret/use the general, structural,

A general formula describes a homologous series, a structural formula shows how atoms are connected, a displayed formula shows all bonds, and a skeletal formula abbreviates the carbon framework.

Convert between representations without changing connectivity. In skeletal formulae, every line end and vertex is a carbon unless labelled otherwise, and hydrogens on carbon are implied to complete valency four.

Propene can be written C₃H₆, CH₃CH=CH₂, a displayed structure or a zig-zag skeletal drawing. All four representations describe the same molecule.

A shorter skeletal drawing is not a different compound. Check the implied carbon and hydrogen counts before naming or calculating formulae.