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.
[Ar] 4s² 3d²
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, 10, 2
Number of electrons in each shell, from the nucleus outwards.
1,668 °C (1,941 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.
3,287 °C (3,560 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).
4.5 g/cm³
Mass of one cubic centimetre of the substance. For gases, at 0 °C and standard pressure.
1.54 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.
6.828 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.
0.076 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.
160 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.
+4, +3, +2
Charges the atom would have in its compounds if all its bonds were ionic; the main ones are listed.
Titanium (Ti) is a chemical element with atomic number 22. It sits in group 4 and period 4 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 47.867.
Origin of the name
Titanium is named after the Titans, the sons of the Earth in Greek myth. In 1791 William Gregor, an English clergyman, found the oxide of an unknown metal in black magnetic sand from a stream in Cornwall. In 1795 Martin Heinrich Klaproth found the same element in rutile; since nothing yet was known of its properties to name it by, he took the name from mythology, and later confirmed that Gregor’s mineral contained titanium too.
Where is titanium found?
Titanium is the ninth most abundant element in the Earth’s crust and is present in nearly every igneous rock. It is mined as the minerals rutile and ilmenite. For a long time the metal was only a laboratory curiosity, because it clings to oxygen; it became an industrial metal once William Kroll found a way to make it from titanium tetrachloride and magnesium, still the main method today.
What is titanium used for?
Most titanium is used as titanium dioxide, the white pigment in house paints and artists’ paints. The metal is as strong as steel but much lighter and does not rust, so it goes into aircraft, rockets and spacecraft, and into ship parts and desalination plants that sit in sea water. The body does not react to it, which makes it the metal of artificial hip joints, bone pins and dental implants.
Interesting facts
Titanium is one of the few elements that burn in pure nitrogen.
Titanium tetrachloride fumes thickly in moist air and has been used to make smoke screens.