All practice pages/Interatomic theory/Elements
Element 22, a transition metal
As strong as many steels at about half the weight, and so friendly to the body that bone grows right onto it.
Period 4, group 4. The other transition metals are tinted, and every cell opens its own article.
Titanium has 22 electrons, one for every proton, so the atom carries no charge. Below are the same 22 electrons written two ways.
1s² 2s² 2p⁶ 3s² 3p⁶ 3d² 4s²
Short form: [Ar] 3d² 4s², where [Ar] stands for the 18 electrons argon already has.
That list runs by shell. In the order the subshells fill it reads [Ar] 4s² 3d², because a subshell fills by its energy, not by its shell number.
The simple form counts electrons shell by shell. The orbital form says which subshell each one sits in: s holds 2, p holds 6, d holds 10 and f holds 14. Shell 3 here is 3s² 3p⁶ 3d², and 2 + 6 + 2 is 10.
Titanium sits in period 4 and has 4 shells. The period number counts the shells.
The outer shell holds 2 electrons. Those are the ones titanium can lose, gain or share, so they are the ones that decide what it bonds with.
Like other transition metals, titanium loses its outer s electrons, and often some d electrons as well, to form positive ions, and it can form more than one kind.
The ninth most abundant element in the crust, in the minerals ilmenite (FeTiO₃) and rutile (TiO₂) found in beach sands and igneous rock. Australia, South Africa and China mine the most.
William Gregor, a clergyman in Cornwall, found an unknown metal in black sand in 1791. Martin Heinrich Klaproth found it again in rutile in 1795 and named it after the Titans of Greek myth. Pure titanium metal was not made until 1910, and the Kroll process that produces it commercially came in the 1940s.
About 95% of titanium ore becomes titanium dioxide, the brilliant white pigment in paint, paper, plastics, toothpaste and sunscreen. The metal goes into jet engines and airframes, hip and knee replacements, dental implants, eyeglass frames and bike frames, and it clads buildings such as the Guggenheim Museum in Bilbao.