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The alkali metals dissolve slowly in liquid ammonia, forming ammoniacal solutions of solvated metal cation M + and solvated electron e −, which react to form hydrogen gas and the alkali metal amide (MNH 2, where M represents an alkali metal): this was first noted by Humphry Davy in 1809 and rediscovered by W. Weyl in 1864.
In chemistry, an alkali (/ ˈ æ l k ə l aɪ /; from the Arabic word al-qāly, القلوي) is a basic, ionic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0.
The alkali metals (lithium, sodium, potassium, rubidium, caesium, and francium) are the most homogeneous column of elements in the periodic table, exhibiting very clear periodic trends. All of them are soft and extremely reactive metals, readily giving up their sole valence electron to form cations.
The alkaline earth metals are six chemical elements in group 2 of the periodic table. They are beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). [ 1 ] The elements have very similar properties: they are all shiny, silvery-white, somewhat reactive metals at standard temperature and pressure .
Rubidium is the second most electropositive of the stable alkali metals and has a very low first ionization energy of only 403 kJ/mol. [12] It has an electron configuration of [Kr]5s 1 and is photosensitive. [15]: 382 Due to its strong electropositive nature, rubidium reacts explosively with water [16] to produce rubidium hydroxide and hydrogen ...
Lithium metal is soft enough to be cut with a knife. It is silvery-white. In air it oxidizes to lithium oxide. [10] Its melting point of 180.50 °C (453.65 K; 356.90 °F) [13] and its boiling point of 1,342 °C (1,615 K; 2,448 °F) [13] are each the highest of all the alkali metals while its density of 0.534 g/cm 3 is the lowest.
A once-common use was the making of tetraethyllead and titanium metal; because of the move away from TEL and new titanium production methods, the production of sodium declined after 1970. [60] Sodium is also used as an alloying metal, an anti-scaling agent, [71] and as a reducing agent for metals when other materials are ineffective.
Francium is an alkali metal whose chemical properties mostly resemble those of caesium. [8] A heavy element with a single valence electron, [9] it has the highest equivalent weight of any element. [8] Liquid francium—if created—should have a surface tension of 0.05092 N/m at its melting point. [10]