Alkali Metal (redirected from Group 1 element)

alkali metal

Any of the six chemical elements in the leftmost group of the periodic table (lithium, sodium, potassium, rubidium, cesium, and francium). They form alkalies when they combine with other elements. Because their atoms have only one electron in the outermost shell, they are very reactive chemically (they react rapidly, even violently, with water), form numerous compounds, and are never found free in nature.

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alkali metal [′al·kə‚lī ‚med·əl]

(chemistry)

Any of the elements of group I in the periodic table: lithium, sodium, potassium, rubidium, cesium, and francium.

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Alkali Metal 

any one of several chemical elements of the major subgroup of Group I of Mendeleev’s periodic system of the elements: lithium, sodium, potassium, rubidium, cesium, and francium. The subgroup’s name is derived from the hydroxides of the alkali metals, called caustic alkalies. The atoms of alkali metals have one s electron in their outer shell and, with the exception of lithium, two 5 electrons and six p electrons in the next to the last shell. The alkali metals always exhibit an oxidation number of +1 in their compounds. They are very reactive chemically. They are oxidized rapidly by atmospheric oxygen and react vigorously with water to form alkalies, MeOH (where Me is a metal). Their reactivity increases from lithium to francium. (See alsoLITHIUM; SODIUM; POTASSIUM; RUBIDIUM; CESIUM; and FRANCIUM.)