1:14a know what is meant by the terms atom
Atom: An atom is the smallest part of an element.
1:16a know what is meant by the terms atomic number, mass number and relative atomic mass (Aᵣ)
Atomic number: The number of protons in an atom.
Mass number: The number of protons and neutrons in an atom.
Relative atomic mass (Ar): The average mass of an atom compared to 1/12th the mass of carbon-12.
1:20a understand how to use electrical conductivity to classify elements as metals or non-metals
Metals
- conduct electricity
Non – Metals
- do not conduct electricity (except for graphite)
1:31a understand how the formulae of simple compounds can be obtained experimentally, including metal oxides
Finding the formula of a metal oxide experimentally
The formulae of metal oxides can be found experimentally by reacting a metal with oxygen and recording the mass changes.
Example: When magnesium is burned in air, it reacts with oxygen (O2) to form magnesium oxide (MgO).
Method:
• Weigh a crucible and lid
• Place the magnesium ribbon in the crucible, replace the lid, and reweigh
• Calculate the mass of magnesium
(mass of crucible + lid + Magnesium – mass of crucible + lid)
• Heat the crucible with lid on until the magnesium burns
(lid prevents magnesium oxide escaping therefore ensuring accurate results)
• Lift the lid from time to time (this allows air to enter)
• Stop heating when there is no sign of further reaction
(this ensures all Mg has reacted)
• Allow to cool and reweigh
• Repeat the heating , cooling and reweigh until two consecutive masses are the same
(this ensures all Mg has reacted and therefore the results will be accurate)
• Calculate the mass of magnesium oxide formed (mass of crucible + lid + Magnesium oxide – mass of crucible + lid)
1:38a understand how to use the charges of these ions in ionic formulae: metals in Groups 1, 2 and 3, non-metals in Groups 5, 6 and 7, Ag⁺, Cu²⁺, Fe²⁺, Fe³⁺, Pb²⁺, Zn²⁺, hydrogen (H⁺), hydroxide (OH⁻), ammonium (NH₄⁺), carbonate (CO₃²⁻), nitrate (NO₃⁻), sulfate (SO₄²⁻)
When given this information of the following ions, it is possible to work out the formulae of ionic compounds which include these ions.
| Name of Ion | Formula | Charge |
|---|---|---|
| Sulfate | SO42- | -2 |
| Carbonate | CO32- | -2 |
| Nitrate | NO3- | -1 |
| Hydroxide | OH- | -1 |
| Ammonium | NH4+ | +1 |
| Silver ion | Ag+ | +1 |
| Zinc ion | Zn2+ | +2 |
| Hydrogen ion | H+ | +1 |
| Copper (II) ion | Cu2+ | +2 |
| Iron (II) ion | Fe2+ | +2 |
| Iron (III) ion | Fe3+ | +3 |
| Lead (II) ion | Pb2+ | +2 |
Ion charges on the periodic table
2:44a describe tests for these gases: hydrogen, carbon dioxide
Test for hydrogen gas (H2)
- Test: use a lit splint
- Result: burns with a squeaky pop
Test for carbon dioxide (CO2)
- Test: bubble through limewater
- Result: limewater turns cloudy
4:03a know what is meant by the term isomerism
Isomers are molecules with the same molecular formula but with a different structure.