Brown's Chemistry AQA GCSE Science-CHEMISTRY 2 Revision Notes
Chemistry Unit C2.1 Structure and bonding
CHEMISTRY UNIT 2 Chemistry 2
for GCSE Additional Science or GCSE Chemistry
REVISION NOTES GUIDE SUMMARY: What do you need to know
for the examinations? What do you need to able to do in the exams? In AQA GCSE Science
A examinations HT means for higher tier students only.
Sorry, but I don't have much time to answer questions, but if you see any
apparent errors or wish to comment, please
email me. All my notes, learning
objectives, comments for exam revision are based on the official AQA GCSE Science A Key Stage 4
Throughout this unit you will be
expected to write word equations for reactions specified.
Higher tier (HT)
candidates will also be expected to write and balance symbol
equations for reactions specified throughout the unit.
AQA GCSE Science CHEMISTRY
Unit C2.1 Structure and bonding
Simple particle theory is
developed in this unit to include atomic structure and bonding.
You should understand that the arrangement of electrons in
atoms can be used to explain what happens when elements react and how atoms
join together to form different types of substances.
You should be able to use
your skills, knowledge and understanding to:
write formulae for ionic
compounds from given symbols and ionic charges.
represent the electronic
structure of the ions in sodium chloride, magnesium oxide and calcium
chloride in the following form:
the sodium ion (Na+)
the chloride ion, the 'blob' electron represents the one gained to form a
chloride ion [2.8.8]- from a chlorine atom [2.8.7].
Hence represent ionic compounds
such as magnesium oxide Mg2+O2-
covalent bonds in molecules such as water H2O, ammonia NH3, hydrogen
chloride HCl, methane CH4 and oxygen O2, and in giant structures such as diamond and
silicon dioxide, in the following forms:
HT only represent the bonding in metals
in the following form:
AQA GCSE Science CHEMISTRY Unit
C2.1.1 Structure and bonding
a) Know that compounds are substances in which atoms of two
or more elements are chemically combined.
b) Know that chemical bonding involves either transferring or
sharing electrons in the highest occupied energy
levels (shells) of atoms in order to achieve the
electronic structure of a noble gas.
c) Know that when atoms form chemical bonds by transferring
electrons, they form ions.
Atoms that lose electrons
become positively charged ions.
Atoms that gain
electrons become negatively charged ions.
have the electronic structure of a noble gas (Group 0).
You should be able to relate the charge on
simple ions to the group number of the element in the
d) Know that the elements in Group 1 of the periodic table, the
alkali metals, all react with non-metal elements to
form ionic compounds in which the metal ion has
a single positive charge.
e) Know that the elements in Group 7 of the periodic table, the
halogens, all react with the alkali metals to form ionic
compounds in which the halide ions have a single
f) Know that an ionic compound is a giant structure of ions.
Know that ionic
compounds are held together by strong electrostatic
forces of attraction between oppositely charged ions.
Understand that these forces act in all directions in the lattice and
this is called ionic bonding.
You should be familiar with the structure of
sodium chloride but do not need to know the
structures of other ionic compounds.
g) Know that when atoms share pairs of electrons, they form
Know that these covalent bonds between atoms are
Know that some covalently bonded substances consist
of simple molecules such as H2, Cl2, O2, HCl, H2O,
NH3 and CH4
Know that others have giant covalent
structures (macromolecules), such as diamond
and silicon dioxide.
You should know the bonding in the examples
in the specification for this unit, and should be able to
recognise simple molecules and giant structures from
diagrams that show their bonding.
h) Know that metals consist of giant structures of atoms arranged
in a regular pattern.
i) HT only: The electrons in the highest occupied energy
levels (outer shell) of metal atoms are
delocalised and so free to move through the
AQA GCSE Additional Science CHEMISTRY
When revising, these pages
provide you with a summary of what you need to know and be able to do.
BUT remember, your primary
source of revision are your class notes, investigations and AQA GCSE
AQA GCSE Additional Science GCSE Chemistry Unit C2 Index:
GCSE Science-Chemistry courses AQA GCSE Science A CHEMISTRY * EDEXCEL GCSE Science
OCR GCSE 21st Century
Science A CHEMISTRY * OCR GCSE Gateway
Science B CHEMISTRY
Science-CHEMISTRY * Northern
Ireland CCEA GCSE Science-CHEMISTRY
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