Elements, compounds and mixtures
Introduced| English | Meaning |
|---|---|
| element/ˈelɪmənt/ | A substance made of atoms with the same proton number. |
| compound/ˈkɒmpaʊnd/ | A substance containing two or more different elements chemically bonded in fixed proportions. |
| mixture/ˈmɪkstʃə/ | A combination of substances that are not chemically bonded together in fixed proportions. |
| Periodic Table/ˌpɪərɪˈɒdɪk ˈteɪbl/ | An arrangement of chemical elements by atomic number that displays recurring patterns in their properties. |
Sorting all matter
- Everything around you is matter — but chemists sort it into three neat groups.
- A substance is an element 元素, a compound 化合物, or a mixture 混合物.
Elements, compounds and mixtures lab
Classify everyday particle examples by composition.
An element is a substance made of:
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Elements contain a single type of atom.
All the known elements are arranged in the ______ Table.
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The Periodic Table lists every element.
Elements
- An element is made of only one type of atom and cannot be broken down chemically.
- The ~118 elements are listed in the Periodic Table 周期表 (e.g. oxygen, iron, carbon).
An element has one type of atom; a compound has different atoms bonded in a fixed ratio; a mixture is not bonded
Water (H₂O) is an example of a:
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Water is hydrogen and oxygen chemically bonded — a compound.
In a compound, the elements are chemically bonded together.
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This is what distinguishes a compound from a mixture.
Compounds
- A compound is two or more elements chemically bonded together.
- Its properties differ from the elements in it, and it can only be separated chemically (e.g. water, H₂O).
A pure element (vanadium): elements are the simplest substances
A mixture can be separated by:
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Mixtures are separated physically (filtering, evaporating).
Mixtures
- A mixture contains two or more substances not chemically joined.
- The parts keep their own properties and can be separated physically (e.g. air, salt water).
A compound is bonded; a mixture is not. In a compound the elements are chemically joined and hard to separate. In a mixture they're just mingled and easy to separate (by filtering, evaporating, etc.).
You've got it
- an element is one type of atom (can't be broken down chemically)
- a compound is elements chemically bonded (separated only chemically)
- a mixture is substances not joined (separated physically)