Materials: Metals and Non-Metals

Materials around us can be classified as metals, such as iron, copper, aluminium and gold, and non-metals, such as sulphur, carbon, oxygen and phosphorus. In this chapter you will compare their physical properties. Metals are generally lustrous, hard, malleable, ductile, sonorous and good conductors of heat and electricity, while non-metals are usually dull, brittle, non-sonorous and poor conductors. You will also meet exceptions: sodium and potassium are soft enough to cut with a knife, mercury is a liquid metal, and graphite, a form of carbon, conducts electricity. You will then study chemical properties. Metals form basic oxides, as magnesium does when it burns, while non-metals such as sulphur form acidic oxides. You will learn why iron rusts, why sodium is stored in kerosene and phosphorus in water, how metals react with acids and bases to release hydrogen, and how a more reactive metal displaces a less reactive one from its salt solution, as zinc displaces copper from copper sulphate. Finally, you will study the uses of metals and non-metals.

Detailed Worksheet: Materials: Metals and Non-Metals Section A - Definitions (10 marks) 1. Define malleability and ductility. Name the most malleable and the most ductile metal used in jewellery. (2 marks) 2. What does it mean to say that a metal is sonorous? Why are school bells made of metal? (2 marks) 3. Name one metal that is a liquid at room temperature and one non-metal that is a liquid at room temperature. Name one non-metal that conducts electricity. (2 marks) 4. What is a displacement reaction? Give one example in words. (2 marks) 5. What is rusting? Name the two substances, besides iron, that are needed for rusting. (2 marks) Section B - Calculations and Applications (15 marks) 6. When 2.4 g of magnesium ribbon is burnt completely in air, 4.0 g of magnesium oxide is formed. (i) Find the mass of oxygen that combined with magnesium. (ii) Write the word equation and the balanced chemical equation. (iii) Is the oxide acidic or basic? How can you test it? (3 marks) 7. Predict whether a reaction will occur, and write the word equation where it does: (i) zinc in copper sulphate solution (ii) copper in zinc sulphate solution (iii) iron in copper sulphate solution. (3 marks) 8. Write balanced chemical equations for: (i) sulphur burning in oxygen to form sulphur dioxide (ii) sulphur dioxide dissolving in water to form sulphurous acid (iii) zinc reacting with dilute sulphuric acid to give zinc sulphate and hydrogen. (3 marks) 9. A student tested five materials and recorded: material P is shiny and can be drawn into wires; Q is dull and breaks into powder on hammering; R is a yellow solid that burns with a blue flame; S is soft and can be cut with a knife and reacts violently with water; T is a liquid metal used in thermometers. Classify each as metal or non-metal and identify R, S and T. (3 marks) 10. Iron nails were kept in three test tubes for a week: tube 1 with tap water and exposed to air, tube 2 with boiled water covered with a layer of oil, tube 3 with dry air and anhydrous calcium chloride. In which tube do the nails rust? Explain the results for all three tubes. (3 marks) Section C - Diagrams (10 marks) 11. Draw a labelled diagram of the activity in which a magnesium ribbon is burnt with a pair of tongs, the ash is collected in a watch glass and dissolved in water, and the solution is tested with red and blue litmus paper. Write the observations. (4 marks) 12. Draw labelled diagrams of two beakers: one with zinc granules in copper sulphate solution and one with a copper strip in zinc sulphate solution. Show the observations after some time. (3 marks) 13. Draw a labelled diagram of the set-up used to test the electrical conductivity of a metal wire and a piece of sulphur using a cell, bulb and wires. (3 marks) Section D - Analysis and Higher-order Thinking (15 marks) 14. Explain the following: (i) Sodium is stored in kerosene. (ii) Phosphorus is stored in water. (iii) Copper vessels develop a green coating over time. (iv) Lemon pickle should not be kept in aluminium utensils. (v) Food cans are coated with tin and not with zinc. (5 marks) 15. Compare metals and non-metals in five physical properties and three chemical properties, giving one example in each case. Explain why graphite and iodine are considered exceptions. (5 marks) 16. A goldsmith claims that gold does not lose its shine even after hundreds of years, while an iron gate rusts within months. Explain this difference in terms of reactivity. Explain why aluminium is used for aircraft bodies and copper for electric wires, and give two uses of non-metals in daily life. (5 marks) Instructions: Time allowed 2 hours. Attempt all sections. Write word equations or balanced chemical equations wherever asked, and perform activities only under supervision.