3.3.1 Intro to organic chemistry

An algerbraic formula that can describe any member of a family of compounds - e.g. CnH2n+1OH (for all alcohols)

The simplest ratio of atoms of each element in a compound - e.g. so ethane, C2H6, has the empircal formula CH3

The actual number of atoms each element in a molecule - e.g. C6H12O6

Show atoms carbon by carbon, with the attached hydrogens and and functional groups

Shows the bonds of the carbon skeleton only, with any functional groups. The hydrogen and carbon atoms aren’t shown. This is handy for drawing large complicated structures, like cyclic hydrocarbons

Shows how all the atoms are arranged, and the bonds between them

A group of compounds that contain the same functional group. The can all be represented by the same general formula

The reactive part of a molecule, it gives most of its chemical properties

• Count the longest continuous chain that contains the functional group - this give you the stem - e.g. 1 = meth-, 4 = but- • The main functional group of the molecules usually gives you the suffix - e.g. ol for alcohols • Number the carbons in the longest carbon chain so that the carbon with the main functional group attached has the lowest possible number ( if there’s more than one longest chain pick the one with the most side chains • Write the carbon number that the functional group is on before the suffix e.g. -2-ol • Any side chains or less important functional groups are added as prefixes at the start of the name, put them in alphabetical order, with the number of the carbon each is attached to • If there’s more than one identical side-chain or functional group, use di (2), tri (3), or tetra (4) before that part of the name - but ignore this when working out the alphabetical order

Two molecules are isomers of one another is they have the same molecular formula but atoms are arranged differently.

Isomers with a different structural arrangment of atoms, the atoms are connected in different ways. They have the same molecular formula but a different structural formula

Chain isomers have different arrangements of the carbon skeleton. Some straight chains and others branched in different ways - e.g butane and methyl propane

Positional isomers have the same carbon skeleton and the same atoms or groups of atoms attached, the difference is that** the atom, or group of atoms is attached to different carbons ** - e.g. 1-chlorobutane and 2-chlorobutane

Functional group isomers have the same atoms arranged into different functional groups - e.g. Hex-1-ene and Cyclo =hexane

Stereoisomers have the same structural formula but a different arrangement in space

Double bonds can’t rotate • Carbon atoms in a C=C double bond and atoms bonded to theses carbons all lie in the same plane • Atoms around C=C double bonds cannot rotate around them like they can around single bonds • The restricted roation around the C=C double bond causes a type of stereoisomerism called E/Z isomerism

Has the same group both above or both bellow the double bond

Has the same group positioned across the double bond

Cahn-Ingold-Prelog (CIP) priority rules are used. • Assign a priority to the two atoms attached to each side in the double bond, the atom with the higher atomic number on each carbon is given priority - e.g. F has an atomic number of 9 and H has an atomic number of 1 so F has priority • Observe how the two higher priority groups are arranged If atoms directly bonded to the carbon are the same then the next atom down the group determines the higher priority