Science Quiz - Atoms and Elements 03 (Answers)
This KS3 Science quiz takes a further look at atoms and elements. Of the 118 known elements, about 90 occur naturally in space or on Earth, but many of them exist in only very small quantities. Most of the elements are combined with each other in the Earth's crust or atmosphere. When elements are combined with other different elements, we say they have formed a compound. Salt is an example of a compound (made from the elements sodium and chlorine joined together), so is water (made from hydrogen and oxygen joined together). There are some that are not very reactive, like gold, and these don't usually form compounds but can be found occuring on their own.
When elements join together to form compounds, their names need to be joined together too. If just two elements join together, one is usually a metal and the other is usually a non-metal. To get the name of the compound, you put the name of the metal first and then change the name of the non-metal to make it end in -ide. This sounds complicated at first but once you get used to it, it is dead easy to do.
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You can find more about this topic by visiting BBC Bitesize - Atoms, elements and compounds
Air is a mixture, fire is not an actual substance, it is just a place where something is burning and water is a compound
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An atom can actually be split into smaller particles called protons, neutrons and electrons but you can't do that using chemicals
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So if you had a sample of a substance that contained only carbon atoms, you would have a sample of the element carbon
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The other three are compounds. A compound is made from different types of atom CHEMICALLY JOINED together. If the different types of atom are not chemically joined together, you have a mixture
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The situation is a bit more complicated when you get more than two elements chemically joined together!
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If the symbol has two letters, the first is a capital and the second is not
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You do not need to know the symbols of all of the elements but it helps your study of science if you know a few
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The others are are all mixtures of two or more elements
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Diatomic = 2 atoms. Element = substance containing only one type of atom
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To remember: when naming a compound with two elements in it, the name of the metal comes first and the name of the non-metal is changed to end in -ide
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