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
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, 8, 2
Number of electrons in each shell, from the nucleus outwards.
819 °C (1,092 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.
1,196 °C (1,469 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).
6.9 g/cm³
Mass of one cubic centimetre of the substance. For gases, at 0 °C and standard pressure.
no data
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.
6.254 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.
no stable negative ion
Energy released when a neutral atom gains an electron. Highest for the halogens. Noble gases, nitrogen and some metals form no stable negative ion.
187 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.
+3, +2
Charges the atom would have in its compounds if all its bonds were ionic; the main ones are listed.
Ytterbium (Yb) is a chemical element with atomic number 70. It sits in period 6 of the periodic table, in the f-block. It is a lanthanide. At room temperature it is a solid. Its standard atomic weight is 173.05.
Origin of the name
Ytterbium is the fourth element named after Ytterby, the Swedish village whose quarry gave so many rare earths. In 1878 Jean Charles Galissard de Marignac found a new oxide, ytterbia, in what was then called erbia. Even that was not one element: in 1907 Georges Urbain split Marignac’s ytterbium into two, ytterbium and lutetium.
Where is ytterbium found?
Ytterbium is obtained together with the other rare-earth elements from their minerals.
What is ytterbium used for?
Ytterbium atoms tick in some of the most precise atomic clocks ever built. Ytterbium-doped optical fibres make powerful lasers, a little ytterbium improves stainless steel, and a radioactive isotope of it has served as the source of portable X-ray devices.