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Description
GCSE AQA Chemistry Atomic Structure and Bonding
1 Atoms
1.1 Atoms consist of a nucleus orbited by electrons
1.2 Protons, neutrons and electrons are sub-atomic particles
1.2.1 Protons
1.2.1.1 The number of protons determines the element
1.2.1.1.1 If an element has only 1 proton it is hydrogen
1.2.1.1.2 If an element has 2 protons it is helium etc....
1.2.1.2 Protons have a relative charge of +
1.2.1.3 Protons have a relative atomic mass of 1
1.2.2 Neutrons
1.2.2.1 Neutrons have a relative charge of 0
1.2.2.2 Neutrons have a relative atomic mass of 1
1.2.2.3
1.2.3 Electrons
1.2.3.1 Electrons have a relative charge of -
1.2.3.2 Electrons have a relative atomic mass of 0
1.3 The nucleus is made up of protons and neutrons
1.4 An atom contains the same number of protons as electrons
1.5 The relative atomic
mass is determined by
the number of protons
added to the number of
neutrons
2 The Periodic Table
2.1 The periodic table is an information source that
displays various properties of different elements
and groups them accordingly
2.2 Elements are listed with symbols that represent them and are used in all formulas
2.2.1 Hydrogen's symbol is H
2.2.2 These can be one or two letters, the first always capitalised
2.2.3 Helium's symbol is He
2.2.4 These symbols are usually either taken
directly from the name or from the same
name in a different language
2.2.4.1 Gold is Au taken from its Latin name aurum
2.2.4.2 Hydrogen is H taken from he start of the word
2.3 Groups
2.3.1 Groups on the periodic table are columns
2.3.2 Groups of elements have similar properties
because they have the same number of
outer shell electrons
2.3.3 Group 8/0 the Noble Gases
2.3.3.1 Helium
2.3.3.2 Argon
2.3.3.3 Krypton
2.3.3.4 Radon
2.3.3.5 Xenon
2.3.3.6 Neon
2.3.3.7 These are unreactive because they
have a full outer shell of electrons
2.3.4 Group 1 the Alkali Metals
2.3.4.1 Potassium
2.3.4.2 Francium
2.3.4.3 Caesium
2.3.4.4 Hydrogen (technically)
2.3.4.5 Rubidium
2.3.4.6 Lithium
2.3.4.7 Sodium
2.3.4.8 These are very reactive as they only have one
electron in their outer shell
2.3.5 The group number is the number of
electrons in the outer shell
2.4 Periods
2.4.1 Periods are rows on the periodic table
2.4.2 The period is the
number of energy shells
or layers an atom has
3 Electron shells
3.1 Electrons orbit the nucleus in energy layers or shells
3.2 The shells can only contain a certain amount of electrons
3.2.1 The first shell can contain 2 electrons
3.2.2 The second shell can only contain 8 electrons
3.2.3 The third shell can hold
more than 8 electrons but at
GCSE level you only need to
know it can hold 8
3.3 Energy shells are filled from the lowest level upwards
3.4 Atoms want to gain a full outer shell
of electrons and so this is why they
react
3.5 Electronic Structure
3.5.1 Electronic structures are diagrams of the energy shells of an atom
3.5.2 The diagram is then
described by a series of
numbers that show the
electron is each shell
3.5.2.1 Carbon is 2.4
3.5.3 Method 1
3.5.3.1 Draw a nucleus, no detail is necessary
3.5.3.1.1 To calculate the electronic
structure find the number of
protons as this is equal to
the number of electrons
3.5.3.1.1.1 Look at the number of
electrons each shell can hold
and calculate how many shells
you need
3.5.3.1.1.1.1 Look at the number of
electrons each shell can hold
and place accordingly filling
from the lowest shell
3.5.4 Method 2
3.5.4.1 Draw the nucleus, no detail is necessary
3.5.4.1.1 Look at the period of the atom and draw that many of energy shells
3.5.4.1.1.1 Look at the group number and fill all the other energy shells up
to the outer shell which you put the group number of electrons in
4 Ionic Bonding
4.1 Ions give or take electrons
4.2 This is held together by electromagnetic forces
4.3 This is between metals and non-metals
4.4 Giant Ionic Lattices
4.5 An ion is a charged particle
4.6 High melting point
4.7 High Boiling Point
4.8 Will carry a current in solution and melted
5 Covalent Bonding
5.1 This is between non-metals
5.2 Atoms share electrons
5.3 Molecules
5.4 Giant Structure
5.4.1 High Melting Point
5.4.2 High Boiling Point
5.4.3 No conduction of electricity (except graphite)
5.4.4 Strong covalent bonds
5.5 Simple Structure
5.5.1 Low Melting Points
5.5.2 Low Boiling Points
5.5.3 No conduction of electricity
5.5.4 Weak intermolecular bonds
