All practice pages/Interatomic theory/Elements
Element 75, a transition metal
The last stable element to be discovered and one of the rarest, now working in the hottest parts of jet engines.
Period 6, group 7. The other transition metals are tinted, and every cell opens its own article.
Rhenium has 75 electrons, one for every proton, so the atom carries no charge. Below are the same 75 electrons written two ways.
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d⁵ 6s²
Short form: [Xe] 4f¹⁴ 5d⁵ 6s², where [Xe] stands for the 54 electrons xenon already has.
That list runs by shell. In the order the subshells fill it reads [Xe] 6s² 4f¹⁴ 5d⁵, 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 4 here is 4s² 4p⁶ 4d¹⁰ 4f¹⁴, and 2 + 6 + 10 + 14 is 32.
Rhenium sits in period 6 and has 6 shells. The period number counts the shells.
The outer shell holds 2 electrons. Those are the ones rhenium can lose, gain or share, so they are the ones that decide what it bonds with.
Like other transition metals, rhenium loses its outer s electrons, and often some d electrons as well, to form positive ions, and it can form more than one kind.
One of the rarest elements in the crust. It is recovered from the molybdenite in copper ores, mainly in Chile and the United States.
Walter Noddack, Ida Tacke and Otto Berg found it in Germany in 1925, detecting it by its X-ray spectrum in platinum ore and columbite, and named it after the Rhine. Ida Tacke, later Ida Noddack, was also the first to suggest, in 1934, that heavy nuclei could split, years before fission was discovered.
Nearly all goes into nickel superalloys for jet engine turbine blades, which must stay strong close to their melting point. Platinum-rhenium catalysts help refine high-octane gasoline, and rhenium makes thermocouples and filaments for mass spectrometers.