Acetic acid has the Lewis dot structure shown below:
Acetic acid is a common carboxylic acid (it is the compound that gives vinegar it's tartness), but behaves much like any other ternary oxy acid.
Organic acids are often written as RCOOH, where the last H is the acid hydrogen and R is the formula for the rest of the molecule.
In this notation, acetic acid become CH3COOH
Other common carboxylic acids:
propionic acid: CH3CH2COOH
benzoic acid: C6H5COOH
butyric acid: CH3CH2CH2COOH