Global Science
Biological Science Tasks - Week 1
Biological Science Tasks - Week 2
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Chemical Science Tasks - Week 1
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Chemical Science Tasks - Week 2
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Earth and Space Science
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ELEMENTS, COMPOUNDS AND MIXTURES
The difference between them.
Elements, Compounds & Mixtures
Elements
:
An element is a substance that cannot be broken down into two or more simpler substances by chemical or physical means.
Note that an element:
* consists of only one kind of atom, each atom is exactly the same size as every other atom.
* cannot be broken down into a simpler type of matter by either physical or chemical means, and
* can exist as either atoms (e.g. argon) or molecules (e.g., nitrogen).
* each element is listed on the periodic table
Compounds:
Microscopic view of the molecules of the compound water (gas phase). Oxygen atoms are red and hydrogen atoms are white.
Note that a compound:
* consists of atoms of two or more different elements
bound together
,
* can be broken down into a simpler type of matter (elements) by chemical means (but not by physical means),
* has properties that are different from its component elements, and
* always contains the same ratio of its component atoms.
Mixtures:
Microscopic view of a gaseous mixture containing two elements (argon and nitrogen) and a compound (water).
Note that a mixture:
* consists of two or more different elements and/or compounds physically intermingled,
* can be separated into its components by physical means, and
* often retains many of the properties of its components.