Minerals, elements and the Earth’s crust: teachers’ notes
This activity is suitable for students aged 11-14.
The activity includes two tables. One gives information about the most common elements in the Earth’s crust and the other the chemical composition of some minerals. Students answer questions based upon the information in these tables. This would be a useful exercise for homework or to be used in the case of teacher absence.
Students need to be familiar with chemical elements, symbols, compounds and formulae.
Reference books and / or internet access should be available to help students tackle the research questions. Alternatively, teachers may wish to make the questions that refer to Table 2 easier, and less dependent on reference sources, by filling in some more of the cells in the table.
About half an hour.
Each student will need a copy of the Periodic Table.
Students tackle a series of questions based on tables giving information about the most common elements in the Earth’s crust and about the chemical composition of some minerals.
Answers to questions
Q 1. Appropriate bar chart.
Q 2. Oxygen.
Q 3. Magnesium.
Q 4. They are found combined because they are relatively reactive elements and combine with oxygen from the atmosphere and with other elements to form compounds.
Q 5. A compound.
Q 6. Magnesium (because it is the rarest). No definite answer is possible because there is no information about the ease of extraction of any of the elements.
Q 7. See Table 1
Table 1 Answers
Q 8. Chalocite has the highest proportion of copper atoms. Chalcopyrite has one copper atom in every four atoms (one quarter, or 25%, of the atoms are copper) whereas in chalcocite it is two copper atoms in every three atoms (two-thirds, or 67%, of the atoms are copper).
Q 9. Chalcocite, because it contains the highest proportion of copper. No definite answer is possible because there is no information about the ease of extraction of copper from either of these minerals, nor about the purity of the ores.
Q 10. See Table 1.
Q 11. Lead: unreactive metal / shiny silver / prehistoric / from Anglo-Saxon / Group 4
Sulfur: reactive non-metal / yellow solid / prehistoric / from Latin / Group 6
Copper: unreactive metal / shiny red-brown / prehistoric / from Cyprus / transition metal
Aluminium: reactive metal / shiny silver / 1826 / from Latin / Group 3
Iron: fairly unreactive metal / shiny silver / ~4000 BC / from Anglo-Saxon / transition metal
Titanium: fairly reactive metal / shiny silver / 1795 / from Latin / transition metal