All practice pages/Interatomic theory/Elements
Element 50, a post-transition metal
The metal that turned copper into bronze and started an age, and the solder that holds electronics together.
Period 5, group 14. The other post-transition metals are tinted, and every cell opens its own article.
Tin has 50 electrons, one for every proton, so the atom carries no charge. Below are the same 50 electrons written two ways.
1s² 2s² 2p⁶ 3s² 3p⁶ 3d¹⁰ 4s² 4p⁶ 4d¹⁰ 5s² 5p²
Short form: [Kr] 4d¹⁰ 5s² 5p², where [Kr] stands for the 36 electrons krypton already has.
That list runs by shell. In the order the subshells fill it reads [Kr] 5s² 4d¹⁰ 5p², 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 3d¹⁰, and 2 + 6 + 10 is 18.
Tin sits in period 5 and has 5 shells. The period number counts the shells.
The outer shell holds 4 electrons. Those are the ones tin can lose, gain or share, so they are the ones that decide what it bonds with. For a main-group element the group number gives that count: group 14 means 4.
Four valence electrons. Tin forms Sn²⁺ or Sn⁴⁺ ions, and also shares electrons in covalent compounds such as tin(IV) chloride.
Mined almost entirely as cassiterite (SnO₂), mainly in China, Indonesia, Myanmar and Peru. Cornwall in England was a major source from the Bronze Age into the 1900s.
Known since ancient times; adding tin to copper made bronze and began the Bronze Age more than 5,000 years ago. The name is Old English, and the symbol Sn comes from its Latin name stannum.
Solder for electronics takes about half. Tin also coats the steel of food cans, which is why they are called tin cans, and makes bronze, pewter and organ pipes. Molten tin is the flat bed on which window glass is floated, and tin compounds stabilize PVC plastic.