The particle pictures show you how the atoms are arranged. These show the thing itself — sulfur's yellow, mercury beading, copper sulfate's blue. Sorted into the same five groups the questions use.
Where it comes fromJust under 1% of the air — the commonest noble gas around us.
What we use it forFilling double glazing, shielding welds from oxygen, and inside filament bulbs.
Why it is in this groupFull outer shell again. Single atoms, drifting alone.
Edelgase in Entladungsroehren.jpg · Alchemist-hp www.pse-mendelejew.de · CC BY-SA 2.0 de
Where it comes fromAs native metal and in ores such as malachite.
What we use it forWiring, water pipes, and roofs — which weather to that pale green.
Why it is in this groupMetal atoms pack in a lattice rather than pairing into molecules.
Natural Copper Ore Macro 1.JPG · “Jon Zander (Digon3)" · CC BY-SA 3.0
Where it comes fromUsually as the native metal, in rock seams and river gravel.
What we use it forJewellery, electrical contacts that must never corrode, and dentistry.
Why it is in this groupSo unreactive it is found uncombined. Still just one kind of atom.
Where it comes fromTrapped underground with natural gas, made by radioactive decay over millions of years.
What we use it forCooling the magnets in MRI scanners, leak testing, and balloons. The supply is genuinely finite.
Why it is in this groupThe full shell it is famous for. It has never been persuaded into a stable compound.
Where it comes fromSmelted from iron ore — the most-used metal on Earth by a wide margin.
What we use it forAlmost everything structural, once mixed into steel. Also the iron in your blood.
Why it is in this groupA lattice of one kind of atom. Same group as neon, for the same reason.
Iron electrolytic and 1cm3 cube.jpg · Alchemist-hp (talk) (www.pse-mendelejew.de) · FAL
Where it comes from0.0018% of the air, separated out by cooling air until it liquefies.
What we use it forThe orange-red glow in neon signs. Other sign colours are other gases, not neon.
Why it is in this groupIts outer shell is already full, so it has no reason to join anything.
Where it comes fromFrom seawater and underground brines.
What we use it forFlame retardants, and once the backbone of photographic film.
Why it is in this groupPairs again. One of only two elements that are liquid in a warm room.
Where it comes fromMade from salt by electrolysis. A green-yellow gas, and toxic.
What we use it forTreating drinking water and pools, bleach, and PVC.
Why it is in this groupOne electron short each, so two atoms pair up and share.
Where it comes fromConcentrated by seaweed, and extracted from brines.
What we use it forAntiseptic, thyroid medicine, and X-ray contrast dyes.
Why it is in this groupPairs, like the rest of its group. Warms straight into a violet vapour.
Iodine crystals.jpg · Jurii. Lanthanum-138 at en.wikipedia · CC BY 3.0
Where it comes from78% of the air. Boils at −196 °C, which is why it is the cheap way to get cold.
What we use it forFreezing food and biological samples, flushing crisp packets, and making ammonia for fertiliser.
Why it is in this groupA triple bond, and a very strong one — which is exactly why the bulk of the air is so unreactive.
Liquidnitrogen.jpg · Cory Doctorow aka gruntzoki on Flickr · CC BY-SA 2.0
Where it comes from21% of the air. Liquid oxygen is a genuine pale blue.
What we use it forBreathing apparatus and hospitals, steel making, and welding torches.
Why it is in this groupTwo atoms share two pairs of electrons — a double bond.
Where it comes fromMade when energy splits O2 and the pieces re-join in threes — by lightning, by a spark, or by UV high in the atmosphere.
What we use it forSterilising water, and the ozone layer that absorbs UV. Down at ground level it is a pollutant and harmful to breathe.
Why it is in this groupThree oxygen atoms joined together. Only one element is involved, so it is molecular elemental — not a compound.
Where it comes fromMined as phosphate rock. The photo shows four different forms of the same element — white, red, violet and black.
What we use it forMatch heads, fertiliser, and detergents.
Why it is in this groupWhite phosphorus is P4: four atoms in a tiny pyramid, each joined to the other three. The red form is a long chain instead — same element, different arrangement.
Where it comes fromVolcanic deposits, and stripped out of crude oil during refining.
What we use it forSulphuric acid — the most-produced industrial chemical there is — plus vulcanised rubber.
Why it is in this groupRings of eight atoms. Molecular, not simple, however solid it looks.
Where it comes fromCarbon dioxide, cooled until it freezes at −78 °C.
What we use it forShipping frozen food and vaccines, and stage fog. It goes straight from solid to gas.
Why it is in this groupA compound: one carbon, two oxygens, every molecule identical.
Where it comes fromMade by reacting copper with sulphuric acid.
What we use it forFungicide on vines, electroplating, and the classic school crystal-growing experiment.
Why it is in this groupMade from copper, and blue. A compound keeps none of its ingredients' properties.
Where it comes fromThe commonest mineral in the crust. Most sand is mostly this.
What we use it forGlass, concrete, and the oscillator in a quartz watch.
Why it is in this groupSilicon and oxygen in a fixed ratio, joined right through.
Where it comes fromWherever iron meets water and air.
What we use it forNothing useful — preventing it is a whole industry.
Why it is in this groupIron joined to oxygen. Flaky and orange, unlike either.
Rusty painted metal diff 16k (Amal Kumar via Poly Haven).jpg · CC0
Where it comes fromEvaporated from seawater or mined as rock salt.
What we use it forFood, road de-icing, and the raw material for chlorine and sodium hydroxide.
Why it is in this groupSodium and chlorine in a fixed one-to-one pattern — and nothing like either on its own.
Where it comes fromTwo-thirds of you, and most of the planet's surface.
What we use it forEverything. Also the standard against which we measure heat capacity.
Why it is in this groupTwo elements locked in a fixed ratio: always two hydrogens to one oxygen.
Where it comes fromAll around you, all the time.
What we use it forBreathing; and it is where we get nitrogen, oxygen, argon and neon from.
Why it is in this groupNitrogen and oxygen molecules side by side, unjoined, evenly spread. A mixture, not a compound.
Field, corn, Liechtenstein, Mountains, Alps, Vaduz, sky, clouds, landscape.jpg · Public domain
Where it comes fromMade deliberately by melting copper with zinc.
What we use it forInstruments, door handles, and fittings that must not spark.
Why it is in this groupAn alloy: two metals sharing a lattice in no fixed ratio, so still a mixture.
Where it comes fromAround 3.5% dissolved salts, mostly sodium chloride.
What we use it forDesalination for drinking water, and evaporation ponds for salt.
Why it is in this groupEvenly mixed all the way through, so homogeneous — but the salt can be evaporated back out.
Where it comes fromIron with a little carbon, plus chromium for stainless.
What we use it forBuildings, cutlery, ships, cars.
Why it is in this groupAlso an alloy. Change the proportions and it is still steel — that is what makes it a mixture.
Dark grey stainless steel heavily scratched worn indented top edge metal surface texture.jpg · CC0
Where it comes fromCooled slowly deep underground, then exposed by erosion.
What we use it forWorktops, kerbstones, and buildings meant to last.
Why it is in this groupYou can see the separate minerals with your eyes. Nothing is joined between them.
Where it comes fromAny kitchen. Shake it and it mixes; leave it and it separates.
What we use it forSalad dressing, and the reason detergents exist.
Why it is in this groupTwo liquids that will not dissolve in each other. Nothing has reacted, so it comes apart again.
Where it comes fromBeaches, riverbeds, deserts.
What we use it forConcrete, glass, and filtration.
Why it is in this groupDifferent grains of different substances, in no fixed ratio. Separable one grain at a time.
Every photograph is freely licensed — CC BY, CC BY-SA, CC0, FAL or public domain — and credited under the picture. Keeping that credit is the whole condition of using them.
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