Alkaline Earth Metals - Key terms



ALKALINE EARTH METALS:

Group 2 on the periodic table of elements, with valence electron configurations of n s 2 . The six alkaline earth metals, all of which are highly reactive chemically, are beryllium, magnesium, calcium, strontium, barium, and radium.

ALKALI METALS:

The elements in Group 1 of the periodic table of elements, with the exception of hydrogen. The alkali metals all have one valence electron in thes1 orbital, and are highly reactive.

CATION:

The positive ion that results when an atom loses one or more electrons. All of the alkaline earth metals tend to form 2+ cations (pronounced KAT-ieunz).

ELECTROLYSIS:

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

ION:

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

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 ofmass. Isotopes may be either stable or unstable—that is, radioactive. Such is the case with the isotopes of radium, a radioactive member of the alkaline earth metals family.

ORBITAL:

A pattern of probabilities regarding the position of an electron for anatom in a particular energy state. The six alkaline earth metals all have valence electrons in an s 2 orbital, which describes a more or less spherical shape.

PERIODS:

Rows of the periodic table of elements. These represent successive principal energy levels in the atoms of the elements involved.

PRINCIPAL ENERGY LEVEL:

A value indicating the distance that an electron may move away from the nucleus of anatom. This is designated by a whole-number integer, beginning with 1 and moving upward. The higher the principal energy level, the greater the energy in the atom, and the more complex the pattern of orbitals.

RADIOACTIVITY:

A term describing a phenomenon whereby certain materials are subject to a form of decay brought about by the emission of high-energy particles. "Decay" in this sense does not mean "rot"; instead, radioactive isotopes continue changing into other isotopes until they become stable.

REACTIVITY:

The tendency for bonds between atoms or molecules to be made or broken in such a way that materials aretransformed.

SALT:

Generally speaking, a compound that brings together a metal and a nonmetal. More specifically, salts (along with water) are the product of a reaction between an acid and a base.

SHELL:

A group of electrons within the same principal energy level.

SUBLEVEL:

A region within the principal energy level occupied by electrons in anatom. Whatever the number n of the principal energy level, there are n sublevels. At each principal energy level, the first sublevel to be filled is the one corresponding to the s orbital pattern—where the alkaline earth metals all have their valence electrons.

VALENCE ELECTRONS:

Electrons that occupy the highest energy levels in anatom, and which are involved in chemical bonding.

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