An element is a simple substance that cannot
be split into anything simpler by chemical
reactions
Atoms are the smallest particles of an element. Atomes of on
element are all the same but are different from atoms of all the
other elements
All the elements are shown in the periodic table
There are 117 known elements, each
element has a chemical symbol, wich i
usually one or two letters
A symbol is written with the first letter as a
capital and the second letter in lower case,
these are examples
Iron - Fe
Aluminium - Al
Oxygen - O
Carbon - C
Compounds
Elements can join together to
make a compound
The name of the compound
tells you the elements that are
in it
Compounds made from two
elements always have a name
that ends in "ide"
Carbon + Oxygen = Carbon Dioxide
Sodium + Chlorine = Sodium Chloride
Magnesium + Oxygen = Magnesium Oxide
A chemical formula tells you the
name and number of atoms in a
compound, the smallest particle of
many compounds is called a
molecule
Molecules are made up of groups of atoms,
some elements are also made of molecules,
for example, a molecule of oxygen contains
two atoms joined together - 02
Water contains two atoms of hydrogen and
one of oxygen - H20
Metals and non-metals
The properties of a substance
describe the way the substance
behaves, or measurements that we
can make on it. Metal and
non-metals have different properties
Non-metals
Most are solids or gases
Dull
Brittle - Break easily and
can not bend very well
Found on the right and
middle of the periodic table
Poor conductors of heat
and electricity
Metals
Good conductors
of heat and
electricity
Shiny
Solids with a high melting point
Mainly found on the
left-hand side and in the
centre of the periodic
table
The metals are magnetic
Re-use and recycling
Materials can be
classified to the
properties.
All the different materials in the world
are made up of about 90 different
elements, some useful materials occur
naturally, but others have to be
manufactured using chemical reactions
In many cases, raw materials are
non-renewable. If we can recycle these
materials, then we reduce the demand for raw
materials. There may also be energy saving as
well
A process that used recycled or renewable
materials is sustainable. Waste can also be
reduced by re-using objects such as glass
bottles or plastic bags