AQA-8462-HODDER-SAMPLE

1 Atomic structure and the periodic table
KEY TERM
Compound Substance made from
different elements chemically joined
together.
Elements reacting
What happens to the
electrons to get full
outer shells
● Reactions between elements
When elements react with each other they form compounds.
Compounds are substances made from different elements bonded
together.
When elements react with each other, electrons are either shared with
other elements or transferred from one element to another. This is
done so that atoms obtain the stable electron structure of the Group 0
elements with only full shells of electrons.
The table shows what happens in general when elements react with
each other.
Type of particles
formed
Non-metal + non-metal Electrons shared Molecules (where atoms
are joined to each other by
covalent bonds)
Metal + non-metal
Metal + metal
Electrons transferred from
metal to non-metal
No reaction as both metals
cannot lose electrons
Type of compound
formed
Simple molecular
compound
Example
Hydrogen reacts with
oxygen by sharing
electrons and forming
molecules of water
Positive and negative ions Ionic compound Sodium reacts with
chlorine by transferring
electrons from sodium to
chlorine to form sodium
chloride which is made
of ions
Test yourself
22 Do the following elements react with each other, and if they do, what
type of compound is formed?
a) potassium + oxygen
b) bromine + iodine
c) oxygen + sulfur
d) sulfur + magnesium
e) calcium + potassium
f) nitrogen + hydrogen
Show you can...
The electronic structures of the atoms of 5 different elements, A, B, C,
D and E, are shown below.
A: 2,8,8 B: 2,8,8,1 C: 2,6 D: 2,1 E: 2,8,7
Using the letters A, B, C, D or E choose:
a) An unreactive element.
b) Two elements found in the same Group of the periodic table.
c) An element whose atoms will form ions with a charge of 2−.
d) Two elements that react to form an ionic compound.
e) Two elements that react to form a covalent compound.
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