All practice pages/Interatomic theory/Elements
Element 78, a transition metal
A precious metal rarer than gold, the catalyst that cleans diesel exhaust, and the core of a widely used cancer drug.
Period 6, group 10. The other transition metals are tinted, and every cell opens its own article.
Platinum has 78 electrons, one for every proton, so the atom carries no charge. Below are the same 78 electrons written two ways.
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 4f¹⁴ 5s² 5p⁶ 5d⁹ 6s¹
Short form: [Xe] 4f¹⁴ 5d⁹ 6s¹, where [Xe] stands for the 54 electrons xenon already has.
That list runs by shell. In the order the subshells fill it reads [Xe] 6s¹ 4f¹⁴ 5d⁹, 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.
Platinum sits in period 6 and has 6 shells. The period number counts the shells.
The outer shell holds 1 electron. Those are the ones platinum can lose, gain or share, so they are the ones that decide what it bonds with.
Like other transition metals, platinum loses its outer s electrons, and often some d electrons as well, to form positive ions, and it can form more than one kind.
Found as native grains and in nickel-copper ores. South Africa's Bushveld Complex supplies about 70% of the world's platinum, with Russia next.
Peoples of pre-Columbian South America worked it into jewelry. Spanish colonists dismissed it as platina, little silver, an annoying impurity in gold, and Antonio de Ulloa described it scientifically in 1748. Its name comes from that Spanish word.
Catalytic converters, especially for diesel vehicles, take the largest share, followed by jewelry and investment bars. Platinum catalysts make nitric acid and refine gasoline, platinum electrodes serve in fuel cells and labs, and cisplatin, a platinum compound, has treated testicular, ovarian and other cancers since the 1970s.