Hydrogen - Key terms





COVALENT BONDING:

A type of chemical bonding in which two atoms share valence electrons.

DIATOMIC:

A term describing an element that exists as molecules composed of two atoms.

DUET RULE:

A term describing the distribution of valence electrons when hydrogen atoms—which end up with only two valence electrons—experience chemical bonding with other atoms. Most other elements follow the octet rule.

ELECTROLYSIS:

The use of an electric current to cause a chemical reaction.

FISSION:

A nuclear reaction involving the splitting of atoms.

FUSION:

A nuclear reaction that involves the joining of atomic nuclei.

HYDROCARBON:

Any chemical compound whose molecules are made up of nothing but carbon and hydrogen atoms.

HYDROGENATION:

A chemical reaction in which hydrogen atoms are added to carbon multiple bonds, as in a hydrocarbon.

ION:

An atom or group of atoms that has lost or gained one or more electrons, and thus has a net electrical charge.

IONIC BONDING:

A form of chemical bonding that results from attractions between ions with opposite electric charges. The bonding of a metal to a nonmetal such as hydrogen is ionic.

ISOTOPES:

Atoms that have an equal number of protons, and hence are of the same element, but differ in their number of neutrons. This results in a difference of mass. An isotope may either be stable or radioactive.

NUCLEUS:

The center of an atom, a region where protons and neutrons are located, and around which electrons spin. The plural of "nucleus" is nuclei.

OCTET RULE:

A term describing the distribution of valence electrons that takes place in chemical bonding for most elements, which end up with eight valence electrons. Hydrogen is an exception, and follows the duet rule.

ORGANIC:

At one time, chemists used the term "organic" only in reference to living things. Now the word is applied to most compounds containing carbon, with the exception of calcium carbonate (lime-stone) and oxides such as carbon dioxide.

RADIOISOTOPE:

An isotope subject to the decay associated with radioactivity. A radioisotope is thus an unstable isotope.

SATURATED:

A term describing a hydrocarbon in which each carbon is already bound to four other atoms.

TRACER:

An atom or group of atoms whose participation in a chemical, physical, or biological reaction can be easilyobserved. Radioisotopes are often used astracers.

UNSATURATED:

A term describing a hydrocarbon, in which the carbons involved in a multiple bond are free to bond with other atoms.

VALENCE ELECTRONS:

Electrons that occupy the highest principal energy level in an atom. These are the electrons involved in chemical bonding.