Alkaline earth metal

Not to be confused with Alkali metal.
Alkaline earth 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
alkali metals ←    → group 3
IUPAC group number 2
Name by element beryllium group
Trivial name alkaline earth metals
CAS group number
(US, pattern A-B-A)
 IIA
old IUPAC number
(Europe, pattern A-B)
 IIA
↓ Period
2
Image: Lump of beryllium
Beryllium (Be)
4
3
Image: Magnesium crystals
Magnesium (Mg)
12
4
Image: Calcium stored under argon atmosphere
Calcium (Ca)
20
5
Image: Strontium floating in paraffin oil
Strontium (Sr)
38
6
Image: Barium stored under argon atmosphere
Barium (Ba)
56
7
Image: Radium electroplated on copper foil and covered with polyurethane to prevent reaction with air
Radium (Ra)
88

Legend

primordial element
element by radioactive decay

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.[2]

Together with helium, these elements have in common an outer s orbital which is full[2][3][4]—that is, this orbital contains its full complement of two electrons, which the alkaline earth metals readily lose to form cations with charge +2, and an oxidation state of +2.[5] Helium is grouped with the noble gases and not with the alkaline earth metals, but it is theorized to have some similarities to beryllium when forced into bonding and has sometimes been suggested to belong to group 2.[6][7][8]

All the discovered alkaline earth metals occur in nature, although radium occurs only through the decay chain of uranium and thorium and not as a primordial element.[9] There have been experiments, all unsuccessful, to try to synthesize element 120, the next potential member of the group.

  1. ^ International Union of Pure and Applied Chemistry (2005). Nomenclature of Inorganic Chemistry (IUPAC Recommendations 2005). Cambridge (UK): RSC–IUPAC. ISBN 0-85404-438-8. pp. 51. Electronic version..
  2. ^ a b Royal Society of Chemistry. "Visual Elements: Group 2–The Alkaline Earth Metals". Visual Elements. Royal Society of Chemistry. Archived from the original on 5 October 2011. Retrieved 13 January 2012.
  3. ^ "Periodic Table: Atomic Properties of the Elements" (PDF). nist.gov. National Institute of Standards and Technology. September 2010. Archived (PDF) from the original on 2012-08-09. Retrieved 17 February 2012.
  4. ^ Lide, D. R., ed. (2003). CRC Handbook of Chemistry and Physics (84th ed.). Boca Raton, FL: CRC Press.
  5. ^ Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
  6. ^ Grochala, Wojciech (1 November 2017). "On the position of helium and neon in the Periodic Table of Elements". Foundations of Chemistry. 20 (2018): 191–207. doi:10.1007/s10698-017-9302-7.
  7. ^ Bent Weberg, Libby (18 January 2019). ""The" periodic table". Chemical & Engineering News. 97 (3). Archived from the original on 1 February 2020. Retrieved 27 March 2020.
  8. ^ Grandinetti, Felice (23 April 2013). "Neon behind the signs". Nature Chemistry. 5 (2013): 438. Bibcode:2013NatCh...5..438G. doi:10.1038/nchem.1631. PMID 23609097.
  9. ^ "Abundance in Earth's Crust". WebElements.com. Archived from the original on 9 March 2007. Retrieved 14 April 2007.