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.
[Kr] 5s² 4d¹
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, 9, 2
Number of electrons in each shell, from the nucleus outwards.
1,522 °C (1,795 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.
3,345 °C (3,618 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).
4.47 g/cm³
Mass of one cubic centimetre of the substance. For gases, at 0 °C and standard pressure.
1.22 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.
6.217 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.
0.311 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.
190 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
Charges the atom would have in its compounds if all its bonds were ionic; the main ones are listed.
Yttrium (Y) is a chemical element with atomic number 39. It sits in group 3 and period 5 of the periodic table, in the d-block. It is a transition metal. At room temperature it is a solid. Its standard atomic weight is 88.906.
Origin of the name
Yttrium is named after Ytterby, a village near Stockholm. In an old quarry there an amateur chemist, Carl Axel Arrhenius, found a heavy black rock, and the Finnish chemist Johan Gadolin discovered in it the oxide of a new element; the mineral was later named gadolinite in his honour. In 1843 Carl Gustaf Mosander showed that this ‘yttria’ was in fact a mixture of the oxides of three elements.
Where is yttrium found?
Yttrium is never found free. It occurs in almost all rare-earth minerals, together with the lanthanides it closely resembles, and is extracted from monazite sand and bastnäsite.
What is yttrium used for?
Yttrium compounds are phosphors: they glowed red on the screens of colour television tubes and today they are used in LEDs. Yttrium aluminium garnet is the crystal at the heart of many lasers and has been sold as imitation diamond, and yttrium iron garnet filters microwave signals.
Interesting facts
The single quarry at Ytterby gave its name to four elements: yttrium, erbium, terbium and ytterbium.