two or more atoms with the same number of protons but different number of neutrons 

they have the same number of electrons in their outer energy level 

Why do isotopes have similar chemical properties?

filtration, crystallisation, simple distillation, fractional distillation, chromatography 

Name 5 separation techniques to separate mixtures 

 1. Set up filter paper in filter funnel 2. Pour mixture onto the filter paper 3. Collect your insoluble salt 

1. gently heat solution using a bunsen burner or water bath until you start seeing crystals 2. use filter paper to separate the crystals 3. leave to cool somewhere warm 

1. Put the crude oil through a chamber and heat until it is a gas 2. Pass the gas through a fractionating column to separate the hydrocarbons by boiling point 3. Collect the hydrocarbons and use as fuels or separate them for other uses

1. Draw a base line and dot of ink on a piece of paper 2. Place the paper in a shallow amount of solvent in a beaker and put the lid on 3. Wait for the ink to move up the paper 4. Take the paper out and leave to dry - the pattern of spots left is called a chromatogram 

the number of electrons = number of protons

metal and non-metal, metal loses electron and becomes positively charged ion and non-metal gains an electron and becomes negatively charged ion

electrostatic forces of attraction between many oppositely charged ions, these forces act in all directions in the lattice 

non-metals, a strong bond consisting of a shared pair of electrons 

inside molecule string covalent bonds example: graphite, diamond, silicon dioxide 

weak intermolecular forces between molecules example: CO2, H20 etc 

metals, positive ions and a cloud of delocalised electrons

electrostatic forces of attraction between positive ions (cations) and cloud of delocalised electrons 

aqueous solution of calcium hydroxide (lime water), gas bubbled through the lime water, if it turns cloudy CO2 is present 

What do aqueous solutions of acids produce? 

What do aqueous solutions of alkalis produce? 

the greater the concentration of hydrogen ions in solution the lower the pH

the hydrogen ions react with the hydroxide ions, also known as the ionic equation for neutralisation 

How do neutralisation reactions between an acid and an alkali produce water? 

What is the ionic equation for neutralisation?

all metal carbonates decompose when heated to form carbon dioxide and a metal oxide - thermal decomposition 

Describe thermal decomposition of carbonates 

giant ionic lattice in which there are strong electrostatic forces of attraction in all directions between oppositely charged ions 

Describe the structure of ionic compounds 

the different sizes of atoms in an alloy distort the layers in the structure making it difficult for them to slide over eachother 

each carbon atom form four covalent bonds with other carbon atoms in a giant covalent structure with a rigid tetrahedral arrangement 

each carbon atom forms 3 carbon-carbon covalent bonds forming layers of hexagonal rings, layers held together by weak intermolecular forces 

layers are free to slide over eachother because there are no covalent bonds between layers 

each silicon atom is joined to 4 oxygen atoms, many covalent bonds 

Describe the structure of silica (silicon dioxide) 

because they have a high surface area to volume ratio 

Why do nanoparticules have different properties from the same material in bulk?

medicine, electronics, cosmetics and suncream, deodorants 

1. Warm 20cm3 of appropriate acid 2. add metal oxide/carbonate until it stops dissolving 3. filter off excess solid, keep filtrate 4. partially evaporate over a water bath 5. leave in a warm, dry place 

1. 10cm3 of appropriate sodium salt solution 2. add 10cm3 of appropriate metal nitrate solution 3. filter and keep residue 4. wash with distilled water 5. leave in a warm,dry place 

year 9 chemistry

Flashcards

GCSE AQA Chemistry paper 2

year 8 chem flashcards /questions

year 9 chemistry

Flashcards

GCSE AQA Chemistry paper 2

year 8 chem flashcards /questions