Tin
Definition and meaning of Tin in chemistry.
![Tin element card: symbol Sn, atomic number 50, atomic mass 118.71, electron configuration [Kr] 4d¹⁰ 5s² 5p², oxidation states +4 +2 -4, Post-transition metal, group 14, period 5, liquid at room temperature.](/assets/images/terms/tin-chemical-element.webp)
Tin is a soft, silvery-white metal with the chemical symbol Sn and an atomic number of 50. This post-transition metal resists corrosion and has a relatively low melting point of 232 degrees Celsius. Its chemical symbol comes from stannum, which is the ancient Latin word for the metal.
In more detail
Tin sits in group 14 on the periodic table as a post-transition metal. The metal has two main crystal forms, which chemists call allotropes. White tin is the stable, metallic form we use at room temperature.
Below 13.2 degrees Celsius, white tin slowly changes into a crumbly gray powder. This cold-weather change is called gray tin, or tin pest. This transformation destroys the strength of the metal and ruins its structure.
Mining companies extract most tin from an oxide mineral called cassiterite. This key mineral contains concentrated tin dioxide, which has the formula SnO2. Tin reacts with other elements to form +2 and +4 oxidation states.
The +4 state is more stable under normal surface conditions. Pure tin resists corrosion from both water and air very well. This makes the metal perfect for coating other vulnerable metals.
The modern glass industry also uses liquid tin on a massive scale. Workers float hot liquid glass on top of molten tin. This clever process makes perfectly flat window sheets with smooth surfaces.
Students often confuse tin cans with pure tin objects. In reality, these cans consist of steel with only a thin tin lining. Another common mistake is calling kitchen foil tin foil. That foil is actually made of aluminum, which replaced tin decades ago.
Key facts
| Field | General Chemistry |
|---|---|
| Symbol | Sn |
| Atomic number | 50 |
| Atomic mass | 118.71 u |
| Category | Post-Transition-Metal |
| Melting point | 231.93 °C |
Food manufacturers use tin to coat the inside of steel cans. This thin layer stops the steel from reacting with acidic food. Without this coating, the iron in the steel would rust quickly. The tin barrier keeps the food safe and fresh for a long time.
Frequently asked questions
Why does white tin change into gray tin in the cold?
Low temperatures cause the atoms in tin to rearrange their shape. This changes the metallic crystal structure into a brittle, nonmetallic structure.
Is tin a safe metal for packaging food?
Yes, tin does not react with food and is safe for humans. It prevents the steel can from rusting and releasing harmful iron.
What is the difference between tin and aluminum foil?
True tin foil is stiff and leaves a slight metallic taste. Aluminum foil is cheaper, thinner, stronger, and replaced tin foil long ago.
Related terms
Sources & references
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