1.4.3Principles of Chemistry
Classify Metals and Non-Metals — Edexcel International GCSE Science Double Award 4SD0 - Chemistry Revision Notes & Topical Questions
5 min read 11 parts Lesson 20 of 50
Part 1 of 5Position in the Periodic Table
Left and right
- Left and right Metals occupy the left and centre of the Periodic Table, and non-metals are found on the right-hand side.
- Most elements are metals.
The staircase line
- The staircase line A stepped line runs down the right-hand side of the table and separates the metals from the non-metals.
Border elements
- Border elements Elements next to the line, such as silicon and germanium, show properties of both types and are called metalloids or semi-metals.
Part 2 of 5Physical properties
| Property | Metals | Non-metals |
|---|---|---|
| Appearance | Usually shiny (lustrous) | Dull |
| State at room temperature | Solid, except mercury which is liquid | Solids, liquids and gases |
| Strength and shape | Malleable and ductile, can be bent and shaped | Brittle when solid, so they shatter or crumble |
| Melting and boiling points | Generally high | Generally low |
| Electrical conductivity | Good conductors | Poor conductors (graphite is a good conductor) |
Part 3 of 5Chemical properties
| Property | Metals | Non-metals |
|---|---|---|
| Outer shell electrons | Usually 1 to 3 | Usually 4 to 7 |
| Bonding | Metallic bonding; atoms tend to lose electrons to form positive ions | Covalent bonding by sharing electrons; may gain electrons to form negative ions |
| Oxides | Basic oxides | Acidic oxides (a few are neutral) |
| Reaction with acids | Many react with acids | Usually do not react with acids |
Part 4 of 5Classifying an unknown element
1
Observe its appearance and state at room temperature, and note whether it is shiny and solid.
2
Test whether it conducts electricity by connecting it in a simple circuit with a cell and lamp.
3
Test whether it is malleable or brittle by gently trying to bend or tap a small sample.
4
Burn it, dissolve the oxide in water and test the solution with indicator, remembering that metal oxides give alkaline solutions and non-metal oxides give acidic ones.
5
Combine the evidence, because a single property can mislead, such as graphite conducting even though carbon is a non-metal.
Part 5 of 5Exceptions to remember
Properties are general trends
Mercury
- Mercury A metal that is liquid at room temperature.
Graphite
- Graphite A form of carbon, a non-metal, that conducts electricity.
Group 1 metals
- Group 1 metals Metals such as sodium are soft and have low melting points compared with most metals.
Key terms
| Term | Meaning |
|---|---|
| Metal | An element that usually conducts electricity, forms basic oxides and loses electrons to form positive ions. |
| Non-metal | An element that usually does not conduct electricity, forms acidic oxides and shares or gains electrons. |
| Malleable | Able to be hammered or bent into shape without breaking. |
| Brittle | Breaks or shatters easily when hit or bent. |
| Lustrous | Having a shiny surface. |
| Metalloid | An element near the staircase line with properties of both metals and non-metals. |
Avoid these mistakes
1
Saying all non-metals are gases. Many are solids such as sulfur and carbon, and bromine is a liquid.
2
Stating that non-metals never conduct electricity and forgetting that graphite is an exception.
3
Mixing up the oxidesmetal oxides are basic, whereas non-metal oxides are acidic.
4
Writing that metals have 4 to 7 outer electrons. Metals usually have 1 to 3.
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