Glossary Part 2

F - O of the Chemistry Glossary. All the terms come from the gloassary of this book. Remember, you can download the entire glossary from here.

F

Free Radical -
A reagent that has an unpaired electron.

G

General Formula -
The formula of a family of organic compounds expressed by using n to represent the number of carbon atoms.

Giant Molecular Structure -
An arrangment of atoms covalently bonded together in such a way that the structure extends indefinetely in 3 dimensions.

Giant Structure -
An arrangement of atoms or ions bonded together in such a way that the structure extends indefinetely in 3 dimensions.

Group -
A vertical column of elements in the Periodic Table. The elements have similar properties because they have the same outer electron arrangement.

Heterolysis -
Describes the breaking down of a covalent bond such that both the electrons in the bond go to one of the atoms and none to the other. The process results in the formation of a positive ion and a negative ion.

Homologous Series -
A set of organic compounds with the same functional group. The compounds differ in the length of their hydrocarbon chains.

Homolysis -
Describes the breaking of a covalent bond such that one of the electrons in the bond goes to one of the formation of a pair of free radicals.

I

Initiation -
The first step of a chain reactions in which a pair of free radicals is formed by bond homolysis.

Intermolecular Forces -
Forces that act between molecules and atoms that are not covalently bonded together (van der Waals forces, dipole-dipole forces and hydrogen bonding).

Ionic Bonding -
A type of bonding between metals and non-metals that is the result of the attraction between the positive metal ions and negative non-metal ions, formed from the transfer of electrons.

Ionisation Energy -
The energy required to remove a mole of electrons from a mole of isolated gaseous atoms.

Ions -
Atoms or molecules that have an overall electrical charge.

Isotopes -
Atoms of the same element (i.e. having the same number of protons) but having different numbers of neutrons.

K

Ketone -
An organic compound inwhich there is a C=O double bond.

L

Leaving Group -
In an organic substitution reaction, the leaving group is an atom or group of atoms that is ejected from the starting material, normally taking with it an electron pair and forming a negative ion.

Lone Pair -
A pair of electrons that is not involved in bonding, in the outer shell of an atom. Also called an unshared pair.

M

Mass Number (or Nucleon Number) -
The total number of neutrons and protons (nucleons) in the nucleus of an atom.

Maxwell-Boltzmann Distribution -
The distribution of energies (and therefore speeds) of the molecules in a gas or liquid.

Metallic Bonding -
A type of bonding found in metals in which positively charged metal ions are held together by their attraction to their pooled sea of outer electrons.

Molecular Formula -
A formula that tells us the numbers of atoms of different elements that make up a molecule of a compound.

Molecular Orbitals -
Volumes of space in which electrons may be found. They spread over two (or more) atoms.

Molecular Structure -
A compound that consists of small molecules.

Molecule -
A small group of atoms held together by covalent bonds.

Monomer -
A small molecule that combines with many other monomers to form a polymer.

N

Neutron -
An uncharged sub-atomic particle found in the nuclei of atoms.

Nucleons -
Protons and neutrons - the sub-atomic particles found in the nuclei of atoms.

Nucleophilic Substitution -
An organic reaction in which a molecule with a partially positively charged carbon atom is attacked by a reagent with a negative charge (a nucleophile). It results in the replacement of one of the groups or atoms on the orginal molecule by the nucleophile.

Nucleus -
The tiny, positively charged centre of an atom composed of protons and neutrons.

O

Orbital -
A volume of space in which an electron or pair of electrons may be found.

Oxidation -
A reaction in which an atom or group of atoms loses electrons.

Oxidation Number -
The number of electrons lost or gained by an atom in a compound compared to the uncombined atom. It forms the basis of a way of keeping track of redox (electron transfer) reactions.

Oxidation State -
An alternative term for oxidation number.

Oxidising Agent -
A reagent that oxidises (removes electron from) another species.

Oxidising Power -
The ability of a reagent to oxidise (remove electron from) another species.