Chemistry Paper 1 (AQA Trilogy)

Atom

The smallest part of an element that can still be recognised as that element

Element

A substance made of only one type of atom

Compound

A substance made of two or more different atoms chemically bonded together

Molecule

A group of atoms chemically bonded together

Mixture

A substance made of more than one thing not chemically bonded together

Three subatomic particles

Protons, neutrons, electrons

Mass of a proton

1

Mass of a neutron

1

Mass of an electron

0

Proton charge

+1

Neutron charge

0

Electron charge

-1

Proton location

Nucleus

Neutron location

Nucleus

Electron location

Shells

Plum pudding model

A ball of positive charge with negative electrons spread throughout

Gold foil experiment

Rutherford fired alpha particles at gold foil. Most went straight through but some were deflected, proving atoms are mostly empty space with a small dense nucleus.

John Dalton

Developed theory of atoms as solid spheres

JJ Thomson

Discovered electrons, developed the plum pudding model of the atom

Ernest Rutherford

Carried out the gold foil experiment, developed the nuclear model of the atom

Niels Bohr

Developed the orbital model of the atom with electrons in shells

Atomic number

The number of protons in an atom

Mass number

The number of protons + the number of neutrons in an atom

Calculate neutron number

Mass number - atomic number

Electron number in the first shell

2

Electron number in the second and third shells

8

Group number (periodic table)

Numbered columns, show how many electrons are in the outer shell

Periods (periodic table)

Rows, show how many shells an atom has

Newland's Law of Octaves

Elements arranged in groups of eight by similar properties

Mendeleev's Periodic table

Elements arranged by atomic weight, gaps left for undiscovered elements

Ion

An atom which has lost or gained an electron

How are the electrons in magnesium arranged?

2.8.2 (12 electrons total)

Electrons in calcium

20

Electrons in silicon

14

Electron arrangement in sulfur

2,8,6

Electron arrangement in magnesium

2,8,2

Outer shell electrons in boron

3

Outer shell electrons in phosphorous

5

Outer shell electrons in sodium

1

Element with three shells and three electrons in the outer shell

Aluminium

Charge of a lithium ion

1+

Charge of a beryllium ion

2+

Charge of an oxide ion

2-

Charge of a fluoride ion

1-

Charge when gaining electrons

Negative

Charge when losing electrons

Positive

Why do atoms transfer electrons in ionic bonding?

So that they can have full outer shells

Giant ionic lattice

A huge 3D network of ions

Melting point of ionic substances

High because strong attractions between oppositely charged ions need lots of energy to break

Aqueous

Dissolved in water

Molten

Melted (liquid)

Electrical conductivity of ionic compounds (solid)

Does not conduct because the ions are not free to move

Electrical conductivity of ionic compounds (molten or dissolved)

Does conduct because the ions are free to move

Soluble

Dissolves in water

Insoluble

Does not dissolve in water

Inert

Unreactive

Noble gas

Group 0 element that is unreactive

Trend

A pattern in properties

Trend in the melting points of the alkali metals

Gets lower going down the group

State of fluorine at room temperature

Gas

State of chlorine at room temperature

Gas

State of bromine at room temperature

Liquid

State of iodine at room temperature

Solid

LiOH

Lithium hydroxide

KOH

Potassium hydroxide

Alkali metal

Group 1 elements that form alkalis when they react with water

Displacement reaction

A reaction in which a more reactive element takes the place of a less reactive element in a compound

Covalent bond

A shared pair of electrons between two non-metals

Ionic bond

An electrostatic attraction between two oppositely charged ions

Giant covalent structures

Diamond, graphite, silicon dioxide

Bonds made by each carbon in diamond

4

High melting point of diamond

Giant structure, Strong covalent bonds between the atoms, requires a lot of energy to break

Electrical conductivity of giant covalent structures

Does not conduct as there are no electrons that are free to move

Electrical conductivity of graphite

Does conduct as delocalised electrons between the layers can move

Graphene

One layer of graphite

Fullerene

Substance made of carbon atoms arranged in a cage

Simple molecular substances

Small molecules containing only a few atoms, for example water (H₂O), methane (CH₄)

Structure of simple covalent molecules

Strong covalent bonds between atoms, weak intermolecular forces holding the molecules together

Intermolecular forces

Weak forces between molecules which hold them together

Melting point of methane

Low as it is a simple molecular substance with weak intermolecular forces that need little energy to break

Polymer

Millions of small molecules joined together in a chain to form a large molecule

Structure of metals

Positive metal ions arranged in layers with delocalised electrons

Delocalised electrons

Electrons that can move and carry a charge

Malleable

Layers of metal ions can slide over each other to form different shapes

Ductile

Layers of metal ions can slide over each other to form wires

Alloy

A mixture of two or more elements, at least one of which is a metal

Properties of alloys

Harder and less reactive

Alloy hardness

Contain different sizes of atoms in the layers which stop them sliding over each other

Reactivity series

A list of elements ordered by their reactivity

Testing reactivity of metals

Add the metals to water or acid and see which ones react the most (by how much fizzing there is)

Electrolysis (extraction)

The process needed to extract metals more reactive than carbon

Ore

A material containing enough metal in it for it to be economically worthwhile to extract the metal

Oxidation

Loss of electrons

Reduction

Gain of electrons

Acid

A substance with a pH of less than 7

H⁺ ions

Released in solution by an acid

State symbol (aq)

Aqueous

HCl (aq)

Hydrochloric acid

H₂SO₄ (aq)

Sulfuric acid

HNO₃ (aq)

Nitric acid