Introduction to Metals and Non-Metals

In the periodic table, elements are generally classified as metals or non-metals based on their physical and chemical properties. Understanding the physical properties of metals and non-metals helps us explain why we use these materials in certain ways, such as why metals are used for building structures and non-metals are used for insulation.

For Year 8 science, we will focus on learning about the differences in physical properties between metals and non-metals.

Key Physical Properties of Metals

Metals have certain characteristics that make them useful in many applications:

1. Shiny Appearance: Metals have a shiny or lustrous surface when polished.
2. Good Conductors of Heat and Electricity: Metals allow heat and electricity to pass through them easily, making them ideal for cooking pots and electrical wiring.
3. High Melting and Boiling Points: Metals generally have high melting and boiling points, making them solid at room temperature (except for mercury).
4. Malleable and Ductile: Metals can be hammered into thin sheets (malleable) or drawn into wires (ductile) without breaking.
5. High Density: Metals usually have a high density, meaning they feel heavy for their size.

Key Physical Properties of Non-Metals

Non-metals have different physical properties that make them suitable for other purposes:

1. Dull Appearance: Most non-metals do not have a shiny appearance.
2. Poor Conductors of Heat and Electricity: Non-metals are generally insulators, meaning they do not conduct heat or electricity well.
3. Low Melting and Boiling Points: Many non-metals have low melting and boiling points and can be gases or brittle solids at room temperature.
4. Brittle: Non-metals are not malleable or ductile; they break easily when struck or bent.
5. Low Density: Non-metals generally have a lower density than metals.

Exam Questions on Physical Properties of Metals and Non-Metals

Here is a set of questions to test your understanding of the physical properties of metals and non-metals, with 20 questions each at easy, medium, and hard levels.

Easy Level Questions

Basic Understanding of Metals and Non-Metals

1. Are metals typically shiny or dull?
2. What is the term for metals that can be hammered into shapes without breaking?
3. Is copper a good conductor of electricity?
4. Are non-metals generally good or poor conductors of heat?
5. What is the physical state of mercury at room temperature?
6. What term describes metals that can be drawn into wires?
7. Do non-metals have high or low density?
8. Are most metals solid, liquid, or gas at room temperature?
9. Is oxygen a metal or a non-metal?
10. Name one use of a metal in everyday life.
11. Which group generally has higher melting points: metals or non-metals?
12. Is graphite a conductor or an insulator of electricity?
13. What property makes metals suitable for electrical wires?
14. Do metals or non-metals tend to be brittle?
15. Are metals generally malleable or brittle?
16. Which property makes metals suitable for making jewellery?
17. Are non-metals usually hard or soft?
18. Is aluminium a metal or a non-metal?
19. What is the appearance of most non-metals?
20. Is gold a good conductor of heat?

Medium Level Questions

Intermediate Knowledge and Comparisons

1. Explain why metals are used for cooking utensils.
2. Why are non-metals poor conductors of electricity?
3. Describe what happens when you try to hammer a piece of coal.
4. Why are metals often used in buildings and construction?
5. Explain why non-metals like plastic are used as insulators in electrical cables.
6. Compare the melting points of metals and non-metals.
7. What makes metals malleable?
8. Is diamond, a form of carbon, a good or poor conductor of electricity?
9. Why is aluminium used for making cans?
10. Explain why graphite, a non-metal, conducts electricity.
11. What is ductility, and which type of element is usually ductile?
12. What happens to most non-metals when they are struck?
13. Describe the density of metals compared to non-metals.
14. Why is copper commonly used in household wiring?
15. Explain why metals are shiny.
16. Why is iron used in construction despite rusting?
17. Why can metals conduct electricity so well?
18. How does the brittleness of non-metals affect their uses?
19. Why are metals generally denser than non-metals?
20. Why is silver used for high-quality jewellery and mirrors?

Hard Level Questions

Advanced Concepts and Applications

1. Explain the atomic structure that makes metals good conductors.
2. Discuss the reasons for the malleability of metals.
3. Why are some metals magnetic and others not?
4. Describe how metallic bonding contributes to metal properties.
5. Explain why non-metals are typically poor conductors of heat.
6. Why does mercury, a metal, exist as a liquid at room temperature?
7. Explain how alloys are made and why they are useful.
8. Compare the atomic arrangement in metals and non-metals.
9. Why is tungsten used in light bulb filaments?
10. Describe the difference in electron movement between metals and non-metals.
11. Why are transition metals harder than alkali metals?
12. Explain why aluminium does not rust like iron.
13. What is metallic bonding, and how does it affect conductivity?
14. Why is stainless steel used for cutlery instead of pure iron?
15. Discuss how density affects the use of metals and non-metals.
16. Why is lead used in shielding for radiation?
17. Explain why metals have high melting points.
18. What causes metals to be shiny?
19. Why do alkali metals react more vigorously than other metals?
20. How does the structure of graphite allow it to be used as a lubricant?

Answers and Explanations

Easy Level Answers

1. Shiny – Metals are typically shiny when polished.
2. Malleable – Metals can be hammered into shapes without breaking.
3. Yes – Copper is an excellent conductor of electricity.
4. Poor conductors – Non-metals generally do not conduct heat well.
5. Liquid – Mercury is a liquid at room temperature.
6. Ductile – Metals can be drawn into wires.
7. Low density – Non-metals generally have a lower density than metals.
8. Solid – Most metals are solid at room temperature.
9. Non-metal – Oxygen is a non-metal.
10. Cooking utensils, jewellery, etc. – Metals have many everyday uses.
11. Metals – Metals generally have higher melting points than non-metals.
12. Conductor – Graphite, an allotrope of carbon, conducts electricity.
13. Conductivity – Metals are good conductors of electricity.
14. Non-metals – Non-metals are more likely to be brittle.
15. Malleable – Metals are generally malleable.
16. Shininess and malleability – These properties make metals suitable for jewellery.
17. Soft – Non-metals are generally softer than metals.
18. Metal – Aluminium is a metal.
19. Dull – Most non-metals appear dull.
20. Yes – Gold is a good conductor of heat.

Medium Level Answers

1. Metals conduct heat well, making them ideal for cooking utensils.
2. Non-metals lack free electrons to carry an electric current.
3. Coal (carbon) would break if hammered because it is brittle.
4. Metals are strong and durable, ideal for building materials.
5. Plastic insulates electricity, preventing accidental electric shocks.
6. Metals have higher melting points than non-metals.
7. The layers in metals can slide, making them malleable.
8. Diamond is a poor conductor of electricity (it has a rigid structure with no free electrons).
9. Aluminium is lightweight and resistant to corrosion.
10. Graphite has free-moving electrons between layers, allowing conductivity.
11. Ductility is the ability to be drawn into wires, a property of metals.
12. Non-metals are brittle and may shatter if struck.
13. Metals are denser than non-metals due to tightly packed atoms.
14. Copper conducts electricity very well.
15. Metals are shiny because they reflect light effectively.
16. Iron is strong and widely available, even though it rusts.
17. Free-moving electrons make metals good conductors.
18. Brittleness limits non-metals to certain applications like insulation.
19. **High density in metals is due to closely packed atoms.**
20. Silver is shiny, reflective, and valuable, ideal for jewellery.

Hard Level Answers

1. Metals have free electrons in a ‘sea’, allowing them to conduct electricity.
2. The atomic layers in metals can slide, making them malleable.
3. Metals like iron are magnetic due to electron alignment; others lack this property.
4. Metallic bonding involves a ‘sea of electrons,’ giving metals their properties.
5. Non-metals lack free-moving electrons to conduct heat effectively.
6. Mercury has a weak bond structure, making it liquid at room temperature.
7. Alloys combine metals for specific properties, like increased strength.
8. Metals have a regular atomic arrangement; non-metals have varied structures.
9. Tungsten has a very high melting point, ideal for filament use.
10. Electrons in metals move freely; in non-metals, they are tightly held.
11. Transition metals have stronger bonds, making them harder.
12. Aluminium forms a protective oxide layer, preventing rust.
13. Metallic bonding allows free electron movement, aiding conductivity.
14. Stainless steel resists rust and is durable, unlike pure iron.
15. High density in metals suits building; low density in non-metals suits insulation.
16. Lead’s high density and atomic structure block radiation.
17. Strong bonds in metals result in high melting points.
18. The ‘sea of electrons’ reflects light, making metals shiny.
19. Alkali metals react vigorously due to their single, easily lost outer electron.
20. Graphite has layers that slide easily, making it a good lubricant.

These questions and answers offer a comprehensive exploration of the physical properties of metals and non-metals, helping Year 8 students prepare effectively for their Key Stage 3 exams.