2, 3 dimethylpentane.

The longest carbon chain in this compound is five carbons in a row (hence pent (5) and ane, from alkane - a carbon-carbon bond (covalent)) - working backwards through the name. There are two separate (they are not linked to each other and are therefore named methyl, if they were linked it would be ethyl and so on) alkyl substituents (a single bond carbon-hydrogen compound off the parent chain), the first substituent is off the second carbon (2) in the parent chain, the second is off the third carbon (3).

So 2, 3 in 2, 3 dimethylpentane gives the position along the carbon chanin that the substituent is bonded to, the di means how many substituents there are, the methyl means substituents are there but only linked from the parent chain (ie not to each other), and the pentane refers to the number of (pent), and type (ane) of carbon compounds on the parent chain.

Hydrocarbons, among the simplest organic compounds found on earth, and yes, my head HURTS.

Ladies and Gentleman, we have begun Organic Chemistry 101.