Alkali Metal

Alkali Metal

The alkali metals are a group in the periodic table consisting of the chemical elements lithium (Li), sodium (Na), potassium (K), rubidium (Rb), caesium (Cs), and francium (Fr). This group lies in the s-block of the periodic table as all alkali metals have their outermost electron in an s-orbital. The alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterized homologous behaviour.

The alkali metals have very similar properties: they are all shiny, soft, highly reactive metals at standard temperature and pressure and readily lose their outermost electron to form cations with charge +1. They can all be cut easily with a knife due to their softness, exposing a shiny surface that tarnishes rapidly in air due to oxidation. Because of their high reactivity, they must be stored under oil to prevent reaction with air, and are found naturally only in salts and never as the free element. In the modern IUPAC nomenclature, the alkali metals comprise the group 1 elements, excluding hydrogen (H), which is nominally a group 1 element but not normally considered to be an alkali metal as it rarely exhibits behaviour comparable to that of the alkali metals. All the alkali metals react with water, with the heavier alkali metals reacting more vigorously than the lighter ones.

All the discovered alkali metals occur in nature: in order of abundance, sodium is the most abundant, followed by potassium, lithium, rubidium, caesium, and finally francium, which is very rare due to its extremely high radioactivity and thus occurs only in traces due to its presence in natural decay chains. Experiments have been conducted to attempt the synthesis of ununennium (Uue), which is likely to be the next member of the group, but they have all met with failure as of 2012. However, ununennium may not be an alkali metal due to relativistic effects, which are predicted to have a large influence on the chemical properties of superheavy elements; even if it does turn out to be an alkali metal, it is predicted to have some differences in physical and chemical properties from its lighter homologues.

Most alkali metals have many different applications. Two of the most well-known applications of the pure elements are rubidium and caesium atomic clocks, of which caesium atomic clocks are the most accurate representation of time known as of 2012. A common application of the compounds of sodium is the sodium-vapour lamp, which emits very efficient light. Table salt, or sodium chloride, has been used since antiquity. Sodium and potassium are also essential elements, having major biological roles as electrolytes, and although the other alkali metals are not essential, they also have various effects on the body, both beneficial and harmful.

Read more about Alkali Metal:  History, Occurrence, Production, Applications, Biological Role and Precautions

Other articles related to "alkali metal, metal, alkali, metals, alkali metals":

Alkali Metal - Biological Role and Precautions
... Sodium and potassium occur in all known biological systems, generally functioning as electrolytes inside and outside cells ... Sodium is an essential nutrient that regulates blood volume, blood pressure, osmotic equilibrium and pH the minimum physiological requirement for sodium is 500 milligrams per day ...
Sodium Selenate - Formation
... The selenous acid is then treated with an alkali metal hydroxide, alkali metal carbonate and/or some other metal oxide/hydroxide to form an alkali metal selenite ...
Alkali Metal Halide
... Alkali metal halides (also known as alkali halides) are the family of inorganic compounds with the chemical formula MX, where M is an alkali metal and X is a halogen ... compounds are the often commercially significant sources of these metals and halides ...
Alkali Hydroxide
... The alkali hydroxides are a class of chemical compounds which are composed of an alkali metal cation and the hydroxide anion (HO-) ... The alkali hydroxides are Lithium hydroxide (LiOH) Sodium hydroxide (NaOH) Potassium hydroxide (KOH) Rubidium hydroxide (RbOH) Caesium hydroxide (CsOH) "A strong base completely ionizes in ... are the hydroxides of Group IA elements and group IIA elements." The most common alkali hydroxide is sodium hydroxide, which is readily available in most hardware stores ...
Crystal Oscillator - Crystal Structures and Materials
... quartz crystals are grown with especially low content of aluminium, alkali metal and other impurities and minimal defects the low amount of alkali metals ... The composition of the growth solution, whether it is based on lithium or sodium alkali compounds, determines the charge compensating ions for the aluminium defects ... tend to trap electrons created during irradiation the alkali metal cations then migrate towards the negatively charged center and form a stabilizing complex ...

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