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What happens to electrons when covalent bonds form?
When covalent bonds form the atoms in the molecule share pairs of electrons.
1 of 18
Describe the physical properties of substances which consist of simple molecules.
Substances that consist of simple molecules are gases, liquids or solids that have relatively low melting and boiling points. They do not conduct electricity because the molecules have no overall charge.
2 of 18
What is a flame test for?
When some metals are put into a flame they give a characteristic colour. To find out what metal ions are present in a compound a flame test can be carried out.
3 of 18
Describe the test for halide ions.
To test for halide ions first add dilute nitric acid to a sample of the compound and then silver nitrate solution. A chloride forms a white precipitate of silver chloride. Bromide forms cream precipitate of Silver Bromide and Silver Iodide is purple.
4 of 18
Name two substances made of giant covalent structures.
Diamond, graphite and silicon dioxide are substances made of giant covalent structures.
5 of 18
Explain why graphite conducts electricity.
In graphite only three of the four outer electrons are used in covalent bonds. The electrons that are not used are free to move through the whole structure. These free electrons allow graphite to conduct electricity.
6 of 18
Why is heating with carbon not a suitable method for extracting aluminium from its ore?
Heating with carbon is not a suitable method for extracting aluminium from its ore because aluminium is higher in the reaction series.
7 of 18
How is aluminium extracted from its ore?
Aluminium is extracted from its ore which contains aluminium oxide by electrolysis. The aluminium oxide is melted at a very high temperature and then electrolysis is carried out in large tanks.
8 of 18
Explain how the extraction of metals involve the reduction of ores.
Reduction is the loss of oxygen in a reaction. The extraction of metals involves reduction of ores because metal oxides are reduced to pure metals.
9 of 18
What electrode do positively charged ions move towards during electrolysis?
Positively charged ions move towards the negative electrode during electrolysis.
10 of 18
What is molten lead bromine separated into during electrolysis?
Molten lead bromine is separated into bromine gas and lead metal.
11 of 18
Explain what happens to the ions at each electrode during electrolysis of molten lead bromide.
During electrolysis at the negative electrode, positively charged lead ions gain electrons (reduction) and at the the positive electrons they lose electrons (oxidation).
12 of 18
What are isotopes?
Atoms of the same element can have different numbers of neutrons and are called isotopes of that element. The different isotopes of an element all have different masses.
13 of 18
what is meant by the therm 'relative atomic mass'?
The relative atomic mass of an element is an average value for the isotopes of the element. It compares the mass of atoms of the element with an atom of carbon-12.
14 of 18
How is the relative formula mass of a compound calculated?
The relative formula mass of a compound is the sum of the relative atomic masses of the atoms in the numbers shown in the formula.
15 of 18
What is meant by the term 'gram formula mass' of a compound?
The gram formula mass of a compound is its relative formula mass in grams.
16 of 18
What makes metals malleable?
Metals can be hammered into shape because the layers of atoms are able to slide over each other if forces are applied to them.
17 of 18
What makes metals such good conductors of heat and electricity?
Metals are good conductors of heat and electricity because electrons in the outer shells of metal atoms are free to move through the whole metal structure.
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Other cards in this set

Card 2

Front

Describe the physical properties of substances which consist of simple molecules.

Back

Substances that consist of simple molecules are gases, liquids or solids that have relatively low melting and boiling points. They do not conduct electricity because the molecules have no overall charge.

Card 3

Front

What is a flame test for?

Back

Preview of the front of card 3

Card 4

Front

Describe the test for halide ions.

Back

Preview of the front of card 4

Card 5

Front

Name two substances made of giant covalent structures.

Back

Preview of the front of card 5
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