Tin

Key takeaways

Tin belongs to chemistry; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Tin to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Tin from memory before moving on to harder problems.

Reference excerpt

Tin is a chemical element; it has the symbol Sn (from Latin stannum) and atomic number 50. A metallic-gray metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. When bent, a bar of tin makes a sound, the so-called "tin cry", as a result of twinning in tin crystals. Tin is a post-transition metal in group 14 of the periodic table of elements. It is obtained chiefly from the mineral cassiterite, which contains stannic oxide, SnO2. Tin shows a chemical similarity to both of its neighbors in group 14, germanium and lead, and has two main oxidation states, +2 and the slightly more stable +4. Tin is the 49th most abundant element on Earth, making up 0.00022% of its crust, and with 10 stable isotopes, it has the largest number of stable isotopes in the periodic table, due to its magic number of protons. It has two main allotropes: at room temperature, the stable allotrope is β-tin, a silvery-white, malleable metal; at low temperatures it is less dense grey α-tin, which has the diamond cubic structure. Metallic tin does not easily oxidize in air or water. The first tin alloy used on a large scale was bronze, made of 1⁄8 tin and 7⁄8 copper (12.5% and 87.5% respectively), from as early as 3000 BC. After 600 BC, pure metallic tin was produced. Pewter, which is an alloy of 85–90% tin with the remainder commonly consisting of copper, antimony, bismuth, and sometimes lead and silver, has been used for flatware since the Bronze Age. In modern times, tin is used in many alloys, most notably tin-lead soft solders, which are typically 60% or more tin, and in the manufacture of transparent, electrically conducting films of indium tin oxide in optoelectronic applications. Another large application is corrosion-resistant tin plating of steel. Because of the low toxicity of inorganic tin, tin-plated steel is widely used for food packaging as "tin cans". Some organotin compounds can be extremely toxic.

Characteristics

Physical

Tin is a soft, malleable, ductile and highly crystalline silvery-white metal. When a bar of tin is bent, a crackling sound known as the "tin cry" can be heard from the twinning of the crystals. This trait is shared by indium, cadmium, zinc, and mercury in its solid state. Tin melts at about 232 °C (450 °F), the lowest in group 14, and boils at 2,602 °C (4,716 °F), the second lowest (ahead of lead) in its group. The melting point is further lowered to 177.3 °C (351.1 °F) for 11 nm particles.

β-tin, also called white tin, is the allotrope (structural form) of elemental tin that is stable at and above room temperature. It is metallic and malleable, and has body-centered tetragonal crystal structure. α-tin, or gray tin, is the nonmetallic form. It is stable below 13.2 °C (55.8 °F) and is brittle. α-tin has a diamond cubic crystal structure, as do diamond and silicon. α-tin does not have metallic properties because its atoms form a covalent structure in which electrons cannot move freely. α-tin is a dull-gray powdery material with no common uses other than specialized semiconductor applications. γ-tin and σ-tin exist at temperatures above 161 °C (322 °F) and pressures above several GPa. In cold conditions β-tin tends to transform spontaneously into α-tin, a phenomenon known as "tin pest" or "tin disease". Some unverifiable sources also say that, during Napoleon's Russian campaign of 1812, the temperatures became so cold that the tin buttons on the soldiers' uniforms disintegrated over time, contributing to the defeat of the Grande Armée, a persistent legend. The α-β transformation temperature is 13.2 °C (55.8 °F), but impurities (e.g. Al, Zn, etc.) lower it well below 0 °C (32 °F). With the addition of antimony or bismuth the transformation might not occur at all, increasing durability. Commercial grades of tin (99.8% tin content) resist transformation because of the inhibiting effect of small amounts of bismuth, antimony, lead, and silver present as impurities. Alloying elements such as copper, antimony, bismuth, cadmium, and silver increase the hardness of tin. Tin easily forms hard, brittle intermetallic phases that are typically undesirable. It does not mix into a solution with most metals and elements so tin does not have much solid solubility. Tin mixes well with bismuth, gallium, lead, thallium and zinc, forming simple eutectic systems. Tin becomes a superconductor below 3.72 K and was one of the first superconductors to be studied. The Meissner effect, one of the characteristic features of superconductors, was first discovered in superconducting tin crystals.

Chemical Tin resists corrosion from water, but can be corroded by acids and alkalis. Tin can be highly polished and is used as a protective coat for other metals. When heated in air it oxidizes slowly to form a thin passivation layer of stannic oxide (SnO2) that inhibits further oxidation.

Isotopes

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Tin

Start with the simplest possible case. Write down what Tin claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In chemistry, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Tin before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Tin ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Tin

In research: Tin appears in chemistry research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Tin in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Tin is common in secondary-school and first-year university syllabi. It links to neighbouring topics Chemical elements, Chemical elements with body-centered tetragonal structure, Native element minerals, so understanding it makes those chapters shorter.
In everyday life: Look for Tin outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

How to study Tin in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Tin means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Tin out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Tin in simple terms?

Tin is a chemical element; it has the symbol Sn (from Latin stannum) and atomic number 50. A metallic-gray metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort.

Why does Tin matter?

Because it connects several chemistry ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Tin?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Tin.