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CLASSIFICATION OF MATTER
VIJITHA V.
PHYSICAL SCIENCE
N.S.S.T.C PANDALAM
REG NO: 13304020
Elements, Compounds and Mixtures
“ single, attached, play play…”
ElementsDefinition of an element:
An element is a pure substance which cannot be split up into two or more
simpler substances by chemical means.
Sugar is not an element as it can be broken down into carbon and water.
Note that an element:
• Consists of only one kind of atom,
• Cannot be broken down into a simpler type of matter by either physical or chemical means
• Can exist as either atoms (e.g. argon) or molecules (e.g., nitrogen).
Elements
Chemical Symbols of Elements
Chemists use symbols to represent elements.
For example, O represents oxygen while Fe represents iron.
Element Symbol Element Symbol
Calcium Ca Mercury Hg
Carbon C Neon Ne
Hydrogen H Silicon Si
Iron Fe Sodium Na
CompoundsNote that a compound:
• 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.
A compound is a substance which is made up of two or more elements chemically combined together.
What is a compound?
- Chemical reactions taking place.
Qn: Is this a compound?
It only contains one type of element.
Qn: Is this a compound?
It only contains one type of element.
H
O
HO
O
Qn: Is this a compound?
It is not chemically combined.
ELEMENTSCOMPOUNDhydrogen
(colourless gas)
oxygen(colourless
gas)
lighted splint
heat, light and
explosion
water(colourless
liquid)
Making compounds from their elementsExample: Making water (picture)
Water molecule
Oxygen molecule
Hydrogen molecule
mixture of
hydrogen and
oxygen
water
Example: Making water (models)
heat, light and
explosion
Summarizing• A compound is made up of two or more
elements chemically joined together• A compound has a fixed composition• Every compound has a unique chemical
formula• A compound has a completely different
properties from its elements• A chemical reaction (decomposition or
electrolysis) is needed to separate the elements in the compound
MixturesDefinition of a mixture:
A mixture is not a pure substance as it contains a mixture of atoms of
molecules which are not chemically combined together.
Mixtures• Note that a mixture: • consists of two or more different elements
and/or compounds NOT chemically combined.• Can be homogeneous or non-homogeneous • can be separated into its components by
physical means, and • often retains many of the properties of its
components.
Mixtures
• Examples of mixtures include muddy water and air.
Air is made up of gases such as nitrogen and oxygen mixed together.
ConclusionAn element is a pure substance which cannot be
split up into two or more simpler substances by chemical means.
A compound consist of a fixed number of different kinds of atoms chemically combined together.
A mixture is not a pure substance as it contains a mixture of atoms of molecules which are not chemically combined together.