CBSE
Class 10 Class 12
On the basis of their chemical composition, substances can be classified either as elements or compounds.
Compound:
Substances that is made up of one or more elements by chemical combination are called compounds, such as water, carbon dioxide, copper oxide, hydrochloric acid, etc. A compound does not contain the properties of its constituent elements and shows quite different characteristics.
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Mixture 1. The components of a mixture may be present in any ratio. |
Compound 1. The components of a compound are always present in a fixed ratio by mass. |
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2. Mixture may be homogeneous or heterogeneous in nature. |
2. Compounds are always homogeneous. |
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3. The components of a mixture can be easily separated by simple physical or chemical means. |
3. The constituents (elements) of the compound cannot be separated either by physical or mechanical means. They can, however, be separated using heat or light (chemical means). |
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4. Components of the mixture can be easily seen with naked eye or with a magnifying glass. |
4. Components of the compound can in no case be seen with naked eye or with a magnifying lens. |
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5. The properties of a mixture are midway between those of its constituents. |
5. The properties of a compound are entirely different from those of its constituents. |
Elements can be normally divided into metals, non-metals and metalloids.
Metals usually show some or all of the following properties:
Examples of metals are gold, silver, copper, iron, sodium, potassium etc. Mercury is the only metal that is liquid at room
temperature.
Non-metals usually show some or all of the following properties:
Examples of non-metals are hydrogen, oxygen, iodine, carbon (coal, coke), bromine, chlorine etc.
Some elements have intermediate properties between those of metals and non-metals, they are called metalloids; examples are boron, silicon, germanium etc.
