The diagram shows part of the structures of caesium chloride and carbon dioxide.
Caesium is a metal.
Describe two properties that are characteristic of most metals.
Magnesium is a metal.
Name and describe the bonding in magnesium.
name:
description of bonding:
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Lead is an excellent roofing material. It is malleable and resistant to corrosion. Lead rapidly becomes coated with basic lead carbonate which protects it from further corrosion.
Lead has a typical metallic structure which is a lattice of lead ions surrounded by a ‘sea’ of mobile electrons. This structure is held together by attractive forces called a metallic bond.
[2]
[2]
Basic lead(II) carbonate is heated in the apparatus shown below. Water and carbon dioxide are produced.
Silica gel absorbs water. Silica gel often contains anhydrous cobalt(II) chloride. When this absorbs water it changes from blue to pink.
Suggest a reason.
3 marksBasic lead(II) carbonate has a formula of the type xPbCO3.yPb(OH)2 where x and y are whole numbers.
Determine x and y from the following information.
PbCO3 → PbO + CO2
Pb(OH)2 → PbO + H2O
When heated, the basic lead(II) carbonate gave 2.112 g of carbon dioxide and 0.432 g of water.
Mass of one mole of CO2 = 44 g
Mass of one mole of H2O = 18 g
Number of moles of CO2 formed = .....................
[1]
Number of moles of H2O formed = .....................
[1]
x = ..................... and y = .....................
Formula of basic lead(II) carbonate is ........................................................................
[1]
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An ore of the important metal zinc is zinc blende, ZnS. This is changed into zinc oxide which is reduced to the impure metal by carbon reduction.
In common with most metals, zinc is a good conductor of electricity. It is used as an electrode in cells.
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For each of the following unfamiliar elements predict one physical and one chemical property.
Caesium (Cs)
Physical property ..............................................................................................................
Chemical property .............................................................................................................
Vanadium (V)
Physical property ..............................................................................................................
Chemical property .............................................................................................................
Fluorine (F)
Physical property ..............................................................................................................
Chemical property .............................................................................................................
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The table below shows the elements in the third period of the Periodic Table, the number of electrons in their outer energy level, their oxidation state in their common compounds and their melting points.
| Element | Na | Mg | Al | Si | P | S | Cl | Ar |
| Number of outer electrons | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| Oxidation state | +1 | +2 | +3 | +4/-4 | -3 | -2 | -1 | 0 |
| Melting point / oC | 98 | 650 | 660 | 1414 | 317 | 115 | -101 | -189 |
Describe and explain the variation in oxidation state across the period.
The first three elements, Na, Mg and Al, are metals.
Describe the structure of a typical metal.
Explain why Na, Mg and Al are good conductors of electricity.
Which element exists as diatomic molecules of the type X2?
Silicon has a similar structure to diamond.
Explain why silicon has the highest melting point in the period.
Sodium chloride is a crystalline solid with a high melting point. It dissolves in water to give a neutral solution. Phosphorus trichloride is a liquid at room temperature. It reacts with water to form an acidic solution.
Suggest an explanation for these differences in properties.
Describe how you could show that magnesium oxide is a basic oxide and not an amphoteric oxide.
Draw a dot-and-cross diagram showing the bonding in magnesium oxide. Show outer electrons only.
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The table shows the melting points, boiling points and electrical properties of five substances, A to E.
| Substance | Melting point / oC | Boiling point / oC | Electrical conductivity of solid |
Electrical conductivity of liquid |
| A | -7 | 59 | poor | poor |
| B | 1083 | 2567 | good | good |
| C | 755 | 1387 | poor | good |
| D | 43 | 181 | poor | poor |
| E | 1607 | 2227 | poor | poor |
Choose a substance from the table above to match each of the following descriptions. A substance may be used once, more than once or not at all. Justify each choice with evidence from the table.
One has been completed as an example.
This substance has a giant covalent structure:
Evidence:
This substance is a metal:
Evidence:
This substance is a liquid at room temperature.
This substance is an ionic solid.
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