S1 – Materials & Chemical Reactions Summary Notes
Atoms & Molecules
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1 – We are developing our understanding of atoms and molecules.
Atoms are the simplest building blocks of every substance in the universe. There
are just over 100 different types of atoms. Elements are made up of only one type
of atom and can be found in the Periodic Table.
The element Oxygen has the
chemical symbol O2 which means
there are two oxygen atoms bonded
together.
When atoms join together they form molecules.
Chemists list all the elements on the Periodic Table where each element has
 a name
 a symbol
 an atomic number
e.g. Magnesium
e.g. Mg
e.g. 12
When writing the symbols the first letter is a CAPITAL followed by a small letter.
In this example we can see the name of the element ‘Carbon’ along with its
symbol ‘C’ (notice this symbol only has one letter which must be a capital).
Using the Periodic Table
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2 – We are developing our knowledge of the periodic table.
Studying the periodic table like the one above we can see that it can be split into
two main sections – Metals and Non-metals. Metals conduct electrical current but
non-metals do not conduct.
Metalloids are elements that have characteristics of both metals and non-metals.
We can also see that each element has a number, which indicates the position of
the element on the periodic table. The number also tells us how many protons each
element has in its nucleus. This number is known as the atomic number.
Hydrogen has the atomic
number 1 which means it has
only one proton in its nucleus.
It can never have any other
atomic number!
If it had two protons it would
no longer be Hydrogen but
instead it would be Helium.
Groups and Periods
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3 – We are developing our knowledge of the periodic table.
Elements in the same column have very similar chemical properties.
 The columns in the periodic table are called GROUPS.
 The rows in the periodic table are called PERIODS.
Some of the groups have special names:
Group 1
Alkali Metals
reactive metals, e.g. sodium
must be stored
under oil
Group 7
Halogens
reactive nonmetals
e.g. chlorine
Group 8
Noble Gases
very unreactive
non-metals
e.g. helium
Solids, Liquids and Gases
4 – We are developing our knowledge of the periodic table.
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 Solid elements have a melting point above room temperature*
 Gas elements have boiling points below room temperature*
 Liquid elements have:
a melting point below room temperature*
a boiling point above room temperature*
*Room temperature is approximately 25oC
Examples:
Water

Melting point = 0oC
Boiling point = 100oC
As room temperature is greater than its melting point it cannot be a solid.
Room temperature is less than its boiling point so it cannot be a gas.
Therefore it must be a liquid.
Gold

Melting point = 1064oC
Boiling point = 2856oC
As room temperature is less than its boiling point it cannot be a gas. Room
temperature is also less than its melting point so it cannot be a liquid and so must
be a solid.

Oxygen
Melting point = - 219oC
Boiling point = - 183oC
As room temperature is greater than its melting point it cannot be a solid.
Room temperature is also greater than its boiling point so it cannot be a liquid.
Therefore it must be a gas.
Elements & Compounds
5 – We are investigating the properties of elements.
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The periodic table consists of many elements with various characteristics and
properties. This makes each element useful for some applications but not for
others.
e.g. Aluminium is a soft, light metal which makes it useful for aeroplane parts and
window frames but not for construction parts like girders that need to be
strong and solid.
The different properties of each element can also be useful if we need to separate
mixtures of elements.
e.g. If Iron and sulphur are added together
they can be easily separated using a
magnet. This is because iron has
magnetic properties and sulphur does
not.
The same iron and sulphur mixture when heated together creates a new substance
that cannot be separated using a magnet. This is because the heat has caused the
iron and sulphur to chemically join (bond) together, creating a new compound
called iron sulphide which does not have magnetic properties.
sulphur
iron
iron sulphide
This chemical reaction can be written as a word equation:
Sulphur
+
Iron =
Iron Sulphide
Other chemical reactions can also be written as a word equation.
e.g. Magnesium
+
Oxygen
=
Magnesium Oxide
As compounds are chemically joined together (bonded) much more energy is
needed to split them up. Whereas mixtures of elements are not bonded together so
are relatively easy to split up.
Naming Compounds
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6 – We are learning how compounds are named.
The name of a compound can tell you the names of the elements that it is made
from. If the compound is sodium chloride (salt)
then the elements are sodium and chlorine.
 The first element in the compound does not change its name and it’s usually
the furthest left in the periodic table or, if in the same group, the furthest up
the table.
e.g. a compound of sulphur and chlorine is called sulphur chloride and
not chlorine sulphide.
 Oxygen is always the second element in an oxide compound.
e.g. you get sulphur oxide, not oxygen sulphide!
Element furthest left comes first when
naming the compound
Element furthest to the right comes second in the compound name
Sodium
+
Chlorine
=
Examples of how compounds are named:
Elements
Compound
magnesium, oxygen
sodium, phosphorus
calcium, iodine
potassium, carbon
lead, sulphur
copper, nitrogen
carbon, oxygen
sulphur, copper
magnesium oxide
sodium phosphide
calcium iodide
potassium carbide
lead sulphide
copper nitride
Carbon oxide
copper sulphide
Sodium Chloride
Chemical Reactions in Air
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7 – We are investigating the reactions of elements and air.
Copper is an element which reacts with oxygen to form a different coloured
compound called copper oxide. The new compound is greater in mass than the
original copper as oxygen has bonded to it. The Statue of Liberty is an example of
this process.
 The statue is made from copper, but even before it
was partly assembled in Paris it had started to
become dull - the copper was reacting with the
oxygen in the air.
 The statue was reassembled in New York in 1886
but within a few years it had turned black since
copper oxide had formed.
 Over many years the black copper oxide reacted
with the small amounts of carbon dioxide in the air.
 The Statue of Liberty eventually turned green.
 The surface was now coated with copper
carbonate.
Investigating Chemical Reactions
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8 – We are investigating the signs of a chemical reaction
During a chemical reaction a new substance is always formed. We can tell that a
chemical reaction has taken place by looking for one or more of the following
changes
1. A colour change
2. An energy change
3. Heat is given out or taken in (and therefore the temperature changes)
4. Light or sound is produced.
5. A new substance is formed (gas or precipitate)
The Reactivity Series
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9 – We are learning to investigate the extraction of useful
substances from natural materials.
Some metals are more reactive than others. Sodium will react when placed in
water, but gold will not be affected by the water at all. The reactivity of a metal
determines how easy it is to extract from rocks in the ground (known as metal
ores). The Reactivity Series is a list of metals shown in their order of reactivity.
Potassium
Sodium
Lithium
Calcium
Magnesium
Aluminium
Zinc
Iron
Tin
Lead
Copper
Mercury
Silver
Gold
(K)
(Na)
(Li)
(Ca)
(Mg)
(Al)
(Zn)
(Fe)
(Sn)
(Pb)
(Cu)
(Hg)
(Ag)
(Au)
Most Reactive
Least Reactive
Making Metals
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10 – We are investigating the extraction of useful substances from
natural materials.
Some metals have been known about for a very long time and their date of
discovery is described as pre-historic, e.g. gold was used in ancient Egyptian times
and before. This is because some metals are found un-combined in the Earth’s
crust. These metals include gold, silver, copper and mercury.
Most other metals are found combined to other elements. Some of these metal
compounds, called ores, can release the metal inside them by heating with carbon,
e.g. iron, lead, tin, copper and zinc.
For example, copper can be extracted from copper carbonate by firstly heating it to
give us copper oxide then heating it again, but this time with carbon, to give us
copper. The following word equation describes the process fully:
1. copper carbonate
copper oxide +
2. copper oxide + carbon
copper +
carbon dioxide
carbon dioxide
Electrolysis
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11 – We are investigating the extraction of useful substances from
natural materials.
Some metals cannot be separated by heating their ores with carbon. Reactive
metals like aluminium require more energy to turn the metal ore compound back to
the pure metal again.
This process is called electrolysis and the energy needed is supplied by passing
an electrical current through the ore. Aluminium, magnesium, sodium and
potassium are made this way.
Copper can be extracted from a solution of copper chloride by passing an electrical
current through it as shown below.