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Organic Chemistry Terms


Alcohols are hydrocarbons that contain a hydroxyl group: -OH. Alcohols are represented by a general formula, which is CnH2n+1OH.


An organic compound containing a functional group: -CHO. This group is always found at the end of the hydrocarbon (or the beginning), but it is never found "internal" to the hydrocarbon. The "R" indicates the location where any kind of hydrocarbon can be placed.


All the single bonds, all the single bonds…Alkanes are hydrocarbons containing only single bonds.


The carbon-carbon double form of hydrocarbons (C=C).


The carbon-carbon triple bond form of hydrocarbon (C=C).


Organic compounds that contain nitrogen, in the form of the functional group: –NH2. The nitrogen in amines contains a lone pair of electrons.

Amino Acids

Organic compounds containing both an amine (-NH2) and a carboxylic acid (-COOH) functional group. Amino Acids are the building blocks of proteins.


A negatively charged ion. Most often this is an atom that has lost a proton.


An alternate term for an aromatic hydrocarbon


A hydrocarbon ring with alternating double and single bonds between carbon atoms. The best example of an aromatic ring is benzene.

Carboxylic Acids

A hydrocarbon containing a functional group consisting of a carbonyl (RR'C=O) and a hydroxyl (R-O-H) group.


A positively charged ion. Most often this is an atom that has lost an electron.

Chiral (also Known As Enantiomers)

An object that cannot be superimposed on its mirror image. Human hands are perhaps the most universally recognized example of chirality, left and right hands look identical except for their opposite orientation.

Chirality Center

An atom with four different atoms or groups attached to it.

Constitutional Isomers

Isomers that differ in the order the atoms are placed. They have the same number of atoms, just in a different order.



Covalent Bond

A chemical bond where two atoms are sharing electrons.


The removal of water from a molecule.


The process by which proteins lose their 3-D (tertiary and secondary) structure by application of an external stress, most often heat.

Double Bond

A bond where four electrons are shared between two atoms.


The strength an atom has to attract electrons towards itself. Electronegative atoms always win at electron tug-of-war.


A molecule that seeks out electrons, also known as a Lewis Acid or an electron pair acceptor.


A hydrocarbon containing a C-O-C unit. Ethers can also be represented as R-O-R'.


A hydrocarbon containing a carbonyl (C=O) adjacent to an ether (C-O-C) linkage.

Free Radicals

A neutral atom containing an unpaired electron.

Functional Groups

An atom, or group of atoms, that is responsible for reactivity of the molecule it is a part of.


An organic molecule containing only hydrogen and carbon atoms.

Hydrogen Bonding

An attractive force between a polar hydrogen atom and an electronegative atom (remember atoms that use the "FON" to make calls: F, O, and N).

Ionic Bond

A chemical bond between two oppositely charged particles (usually a cation and an anion). This bond works like a magnet: opposites attract.


Compounds that have the same molecular formula but different structural formulas. For example, pentane and isopentane have the same molecular formula, but their different structural formula gives them different physical properties: same molecules, different order.


A functional group consisting of an internal carbonyl group (C=O) bonded to two other carbon atoms, represented by the drawing:

Lewis Structure

A chemical formula where electrons are represented with dots. Covalent bonds are represented with a line connecting two atoms—the line represents two electrons.

Molecular Formula

Shows the number and kinds of atoms in a molecule.

Nucleic Acids

Biological molecules, such as DNA and RNA, composed of a nitrogen base, a pentose sugar, and a phosphate group.


An atom that has an unshared electron pair.

Octet Rule

When forming compounds, atoms gain, lose, or share electrons so that their number of valence electrons equals 8.


Large macromolecules composed of many similar (sometimes identical) smaller molecules, or monomers, linked together.


A polypeptide composed of amino acids bonded together by peptide bonds.


The ability of electrons to "shuffle," or alternate, between bonds, making the molecule extremely stable. The best example of this is benzene.


The "3-D" arrangements of hydrocarbons.


Molecules that have the same molecular formula and sequence of atoms yet differ in their 3-D orientation.

Triple Bond

A bond where six electrons are shared between two atoms.

Unsaturated Hydrocarbons

A hydrocarbon that can undergo addition reactions, meaning it contains a double or a triple bond.

Valence Electrons

The outermost electrons of an atom.

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