Alkali metal

  • alkali metals
    hydrogen helium
    lithium beryllium boron carbon nitrogen oxygen fluorine neon
    sodium magnesium aluminium silicon phosphorus sulfur chlorine argon
    potassium calcium scandium titanium vanadium chromium manganese iron cobalt nickel copper zinc gallium germanium arsenic selenium bromine krypton
    rubidium strontium yttrium zirconium niobium molybdenum technetium ruthenium rhodium palladium silver cadmium indium tin antimony tellurium iodine xenon
    caesium barium lanthanum cerium praseodymium neodymium promethium samarium europium gadolinium terbium dysprosium holmium erbium thulium ytterbium lutetium hafnium tantalum tungsten rhenium osmium iridium platinum gold mercury (element) thallium lead bismuth polonium astatine radon
    francium radium actinium thorium protactinium uranium neptunium plutonium americium curium berkelium californium einsteinium fermium mendelevium nobelium lawrencium rutherfordium dubnium seaborgium bohrium hassium meitnerium darmstadtium roentgenium copernicium nihonium flerovium moscovium livermorium tennessine oganesson
    noble gases  alkaline earth metals
    iupac group number 1
    name by element lithium group
    trivial name alkali metals
    cas group number
    (us, pattern a-b-a)
    ia
    old iupac number
    (europe, pattern a-b)
    ia

    ↓ period
    2
    image: lithium metal stored under paraffin
    lithium (li)
    3
    3
    image: sodium metal
    sodium (na)
    11
    4
    image: potassium metal
    potassium (k)
    19
    5
    image: rubidium metal in a glass ampoule
    rubidium (rb)
    37
    6
    image: caesium metal in a glass ampoule
    caesium (cs)
    55
    7 francium (fr)
    87

    legend

    primordial
    element by radioactive decay
    atomic number color:
    black=solid

    the alkali metals consist of the chemical elements lithium (li), sodium (na), potassium (k),[note 1] rubidium (rb), caesium (cs),[note 2] and francium (fr). together with hydrogen they constitute group 1,[note 3] which lies in the s-block of the periodic table. all alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in their having very similar characteristic properties.[note 4] indeed, the alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterised homologous behaviour. this family of elements is also known as the lithium family after its leading element.

    the alkali metals 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 by atmospheric moisture and oxygen (and in the case of lithium, nitrogen). 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 elements. caesium, the fifth alkali metal, is the most reactive of all the metals. all the alkali metals react with water, with the heavier alkali metals reacting more vigorously than the lighter ones.

    all of the discovered alkali metals occur in nature as their compounds: 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; francium occurs only in minute traces in nature as an intermediate step in some obscure side branches of the 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; none were successful. 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. one of the best-known applications of the pure elements is the use of rubidium and caesium in atomic clocks, of which caesium atomic clocks form the basis of the second. a common application of the compounds of sodium is the sodium-vapour lamp, which emits light very efficiently. table salt, or sodium chloride, has been used since antiquity. lithium finds use as a psychiatric medication and as an anode in lithium batteries. 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.

  • history
  • occurrence
  • properties
  • periodic trends
  • compounds
  • representative reactions of alkali metals
  • extensions
  • pseudo-alkali metals
  • production and isolation
  • applications
  • biological role and precautions
  • notes
  • references

Alkali metals
Hydrogen Helium
Lithium Beryllium Boron Carbon Nitrogen Oxygen Fluorine Neon
Sodium Magnesium Aluminium Silicon Phosphorus Sulfur Chlorine Argon
Potassium Calcium Scandium Titanium Vanadium Chromium Manganese Iron Cobalt Nickel Copper Zinc Gallium Germanium Arsenic Selenium Bromine Krypton
Rubidium Strontium Yttrium Zirconium Niobium Molybdenum Technetium Ruthenium Rhodium Palladium Silver Cadmium Indium Tin Antimony Tellurium Iodine Xenon
Caesium Barium Lanthanum Cerium Praseodymium Neodymium Promethium Samarium Europium Gadolinium Terbium Dysprosium Holmium Erbium Thulium Ytterbium Lutetium Hafnium Tantalum Tungsten Rhenium Osmium Iridium Platinum Gold Mercury (element) Thallium Lead Bismuth Polonium Astatine Radon
Francium Radium Actinium Thorium Protactinium Uranium Neptunium Plutonium Americium Curium Berkelium Californium Einsteinium Fermium Mendelevium Nobelium Lawrencium Rutherfordium Dubnium Seaborgium Bohrium Hassium Meitnerium Darmstadtium Roentgenium Copernicium Nihonium Flerovium Moscovium Livermorium Tennessine Oganesson
IUPAC group number 1
Name by element lithium group
Trivial name alkali metals
CAS group number
(US, pattern A-B-A)
IA
old IUPAC number
(Europe, pattern A-B)
IA

↓ Period
2
Image: Lithium metal stored under paraffin
Lithium (Li)
3
3
Image: Sodium metal
Sodium (Na)
11
4
Image: Potassium metal
Potassium (K)
19
5
Image: Rubidium metal in a glass ampoule
Rubidium (Rb)
37
6
Image: Caesium metal in a glass ampoule
Caesium (Cs)
55
7 Francium (Fr)
87

Legend

primordial
element by radioactive decay
Atomic number color:
black=solid

The alkali metals consist of the chemical elements lithium (Li), sodium (Na), potassium (K),[note 1] rubidium (Rb), caesium (Cs),[note 2] and francium (Fr). Together with hydrogen they constitute group 1,[note 3] which lies in the s-block of the periodic table. All alkali metals have their outermost electron in an s-orbital: this shared electron configuration results in their having very similar characteristic properties.[note 4] Indeed, the alkali metals provide the best example of group trends in properties in the periodic table, with elements exhibiting well-characterised homologous behaviour. This family of elements is also known as the lithium family after its leading element.

The alkali metals 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 by atmospheric moisture and oxygen (and in the case of lithium, nitrogen). 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 elements. Caesium, the fifth alkali metal, is the most reactive of all the metals. All the alkali metals react with water, with the heavier alkali metals reacting more vigorously than the lighter ones.

All of the discovered alkali metals occur in nature as their compounds: 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; francium occurs only in minute traces in nature as an intermediate step in some obscure side branches of the 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; none were successful. 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. One of the best-known applications of the pure elements is the use of rubidium and caesium in atomic clocks, of which caesium atomic clocks form the basis of the second. A common application of the compounds of sodium is the sodium-vapour lamp, which emits light very efficiently. Table salt, or sodium chloride, has been used since antiquity. Lithium finds use as a psychiatric medication and as an anode in lithium batteries. 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.