TWEED RIVER HIGH SCHOOL
2006
PRELIMINARY CHEMISTRY
Unit 1
The Chemical Earth
Part 2

Although most elements are found in combinations on
Earth, some elements are found uncombined.
Abundance of Elements in zones of the Earth.
1. The lithosphere:
Element
% by weight
Oxygen
50.0
Silicon
26.0
Aluminium
7.5
Iron
5.0
Calcium
3.5
1
2. The Hydroshpere:
Element
% mass
Oxygen
86.0
Hydrogen
10.75
Chlorine
1.90
Sodium
1.06
3. The Biosphere (Living Cell)
Element
% Mass
Oxygen
60.0
Carbon
21.0
Hydrogen
11.0
Nitrogen
3.5
Calcium
2.5
4. The Atmosphere: As per part 1
2

Explain the relationship between the reactivity of an
element
and
the
likelihood
of
it
existing
and
an
uncombined element.
Reactivity of elements.
The reactivity of an element, in general, depends on the number of
electrons in its outer shell.
Elements in Groups 1 , 2, 3, 5, 6 and 7 are very reactive and are
not found in their elemental state in nature.
The group 8 elements, the noble gases are not reactive and are
found in their elemental state in nature.
Some metals such as gold and silver are also unreactive and are
found in their natural state in nature.

Classify elements as metals, non-metals and semi-metals
according to their physical properties.
1. Metals
Typical metals share the following physical properties:

Relatively high densities.

Good conductors of heat and electricity

Malleable and ductile.

Have a shiny surface (Lustre)

Relatively high melting points
2. Non-Metals

State and form is variable

Usually not lustrous

Poor conductors of heat and electricity

Not malleable or ductile

Variable melting points
3
3. Semi-Metals

Also known as metalloids

Semi-metals have a wide rage of properties which are a
combination of the properties of metals and non-metals.
Practical Assignment

Plan and perform an investigation to examine some
physical properties, including malleability, hardness and
electrical conductivity and some uses of a range of
common elements to present information about the
classification of elements as metals, non-metals and
semi-metals.
Your investigation must include the following points:

Aim

Risk Assessment

Method

Results

Discussion

You will then perform the experiment in the lab.
You will be given a list of elements available to you.
4
Assignment

Analyse
information
from
secondary
sources
to
distinguish the physical properties of metals and nonmetals.
You are to prepare a table outlining to outline the different physical
properties of metals and non-metals. Place the table in the space
below.
5

Account for the uses of metals and non-metals in terms of
their physical properties.
Choosing the right metal for the job
Metal
Properties
Uses
aluminium
low density, does not suitable for the bodies
corrode
copper
good
of planes
conductor
of electrical wires as it is a
electricity, does not good conductor
react with water
water pipes due to its
low reactivity
gold
very good conductor electrical
of
connections
electricity, on circuit boards - due
unreactive
to its conductivity
jewellery - due to its
lack of reactivity
steel
cheap and strong
suitable
material
6
for
building
7
Assignment

Process information from secondary sources and use a
Periodic
Table
to
present
information
about
the
classification of elements as:
-
metals. non-metals and semi-metals
-
solids. Liquids and gases at 25°C and normal
atmospheric pressure.
Use the following two Periodic Tables to present your information.
Use the first Periodic Table to represent metals, non-metals and
semi-metals, and the second Periodic Table to represent solids,
liquids and gases.
8