The lanthanides and actinides, elements in which the f atomic orbitals are being filled.

face-centered cubic

A lattice structure having atoms in the center of each face and at each corner of a cube, abbreviated fcc.

Fahrenheit

The temperature scale defined by the values 32 °F for the freezing point of water and 212 °F for the boiling point of water.

family

Those elements that comprise a single column of the periodic table.

Faraday

The charge associated with a mole of electrons, 96,485 C/mol.

Faraday constant

The electric charge carried by one mole of electrons, 9.648 670 x 10⁴ C mol^-1; abbreviated F.

Faraday's law

The proportionality between the number of moles of a substance produced or consumed in an electrochemical cell and the amount of electricity that passes through the electrical circuit of the cell.

fat

A molecule that is an ester of glycerol and three fatty acids.

fatty acid

A long-chain carboxylic acid that is a component of the triglycerides which constitute fat.

fcc

Abbreviation for face-centered cubic; a lattice structure having atoms in the center of each face and at each corner of a cube.

ferromagnetic

Able to acquire a permanent magnetization.

filtration

The process of separating a solid from a liquid by permitting the liquid to pass through a filter.

first law of thermodynamics

A formal statement of the conservation of energy as applied to chemical systems; the change in internal energy is equal to the sum of the heat added to a system plus the work done to the system.

first-order reaction

A reaction for which the rate is directly proportional to the concentration of one reactant.

fission

A nuclear reaction in which large nuclei break apart to form smaller ones.

formal charge

A quantity useful for predicting reactivity patterns of molecules. Its value is found by dividing bonding electrons equally between bonded atoms and calculating the resulting charge on each atom.

formation constant

An equilibrium constant for a reaction in which a product of interest is formed; often applied to the formation of a complex ion from the central metal ion and ligands.

formula weight

The mass of one mole of a formula unit of a substance; molar mass.

free energy

A thermodynamic function corresponding to the tendency for spontaneous change in a system; represented by the symbol G.

freezing

The process of forming a solid from a liquid.

freezing point

The temperature at which a liquid becomes a solid; also called melting point.

freezing point depression

The decrease in the freezing point of a liquid as a result of the presence of a solute.

frequency

The rate at which a periodic event occurs; specifically, the rate at which the waves of electromagnetic radiation pass a point.

fuel cell

An electrochemical cell in which the reactants are supplied on a continuing basis.

functional group

A set of atoms in a molecule that confer on the molecule a characteristic set of physical and chemical properties.

fusion

A nuclear reaction in which small nuclei are united to form larger ones.