Average mass of an atom in unified atomic mass units (1 u is 1/12 of the mass of a carbon-12 atom). Accounts for the natural mix of the element’s isotopes.
Number of the vertical column, 1 to 18 in IUPAC numbering. Elements in a group share the same outer-shell layout, so their properties are alike.
Number of the horizontal row. Usually equal to the number of electron shells in the atom; palladium is the exception, with four shells in period 5.
The subshell (s, p, d or f) that receives the last electrons in the usual filling order; it divides the table into four blocks. Real atoms sometimes differ: lanthanum starts the f-block but has no f electrons.
[Xe] 6s² 4f¹⁴ 5d¹⁰ 6p³
How electrons are arranged in subshells. The bracket stands for the previous noble gas; the superscript is the number of electrons in a subshell.
2, 8, 18, 32, 18, 5
Number of electrons in each shell, from the nucleus outwards.
271.4 °C (544.55 K)
Temperature at which the solid turns liquid at standard pressure. Helium, carbon and arsenic do not melt at normal pressure: helium needs about 25 atm, carbon and arsenic turn straight into vapour.
1,564 °C (1,837 K)
Temperature at which the liquid boils at standard pressure. For carbon and arsenic, the temperature at which the solid turns straight into vapour (sublimation).
9.807 g/cm³
Mass of one cubic centimetre of the substance. For gases, at 0 °C and standard pressure.
2.02 Pauling
How strongly an atom pulls electrons towards itself in a chemical bond. On the Pauling scale it runs from 0.79 for caesium to 3.98 for fluorine.
7.286 eV
Energy needed to remove the most loosely bound electron from an atom. The lower it is, the more easily the element gives up an electron, which is typical of metals.
0.942 eV
Energy released when a neutral atom gains an electron. Highest for the halogens. Noble gases, nitrogen and some metals form no stable negative ion.
148 pm
Half the length of a single covalent bond between two atoms of the element. It shows the size of an atom inside a molecule or crystal: 76 pm for carbon, 132 pm for iron.
+5, +3
Charges the atom would have in its compounds if all its bonds were ionic; the main ones are listed.
Bismuth (Bi) is a chemical element with atomic number 83. It sits in group 15 and period 6 of the periodic table, in the p-block. It is a post-transition metal. At room temperature it is a solid. Its standard atomic weight is 208.98.
Origin of the name
The name comes from the German Wismut, whose origin is uncertain: it has been explained as weiße Masse, ‘white mass’, and as coming from old mining words. For centuries bismuth was confused with lead and tin, until Claude François Geoffroy showed in 1753 that it was a separate metal.
Where is bismuth found?
Bismuth is sometimes found as the native metal, but most of it is obtained as a by-product of refining lead, copper and tin.
What is bismuth used for?
Bismuth compounds are used in medicines that soothe the stomach. With tin, lead or cadmium, bismuth forms alloys that melt at low temperatures, used in automatic fire sprinklers and electrical fuses. Bismuth compounds also give pigments for cosmetics and paints.
Interesting facts
For a long time bismuth was thought to be the heaviest stable element. Only at the beginning of the 21st century was it shown to be very slightly radioactive: its half-life is more than a billion times the age of the universe.
Grown in the laboratory, bismuth forms stepped crystals that shimmer in all the colours of the rainbow because of a thin layer of oxide.