GCSE Chemistry revision

Metals and non-metals

The periodic table

AQA 4.1.2.3 Foundation & Higher

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Most elements are metals, and they are found towards the bottom-left of the periodic table, whilst non-metals are found towards the top-right.
Metals form positive ions when they react (e.g. calcium forms Ca²⁺), whereas non-metals either form negative ions (e.g. chloride, Cl) or do not form ions at all (e.g. carbon).

1. Position of Metals and Non-Metals on the Periodic Table AQA

Most elements are metals, and they are found towards the bottom-left of the periodic table, whilst non-metals are found towards the top-right.
Metals form positive ions when they react (e.g. calcium forms Ca²⁺), whereas non-metals either form negative ions (e.g. chloride, Cl) or do not form ions at all (e.g. carbon).

Atoms are stable when they have a full outer shell of electrons, which drives them to either lose or gain electrons during reactions.
Metals on the left of the periodic table have few electrons in their outer shell (e.g. calcium in Group 2 has 2 electrons), making it easy to lose them and form positive ions.
Non-metals like chlorine have 7 outer electrons, so losing all of them to form a positive ion would require too much energy — instead they gain electrons to form negative ions.

2. Electron Arrangements and Ion Formation AQA

Atoms are stable when they have a full outer shell of electrons, which drives them to either lose or gain electrons during reactions.
Metals on the left of the periodic table have few electrons in their outer shell (e.g. calcium in Group 2 has 2 electrons), making it easy to lose them and form positive ions.
Non-metals like chlorine have 7 outer electrons, so losing all of them to form a positive ion would require too much energy — instead they gain electrons to form negative ions.

Elements further down the periodic table have more electron shells (e.g. lead has 6 shells), placing the outer electrons much further from the nucleus.
The greater the distance between the outer electrons and the positive nucleus, the weaker the attraction holding those electrons in place.
This means metals lower in a group lose their outer electrons more easily during reactions, making them more reactive.

3. Why Reactivity Increases Down a Group for Metals AQA

Elements further down the periodic table have more electron shells (e.g. lead has 6 shells), placing the outer electrons much further from the nucleus.
The greater the distance between the outer electrons and the positive nucleus, the weaker the attraction holding those electrons in place.
This means metals lower in a group lose their outer electrons more easily during reactions, making them more reactive.

Metals have metallic bonding, a strong type of bonding unique to metals that is responsible for their characteristic physical properties.
Metals are malleable, meaning they can be bent or hammered into shape without snapping.
Metals are excellent conductors of heat and electricity, which is why they are used in electrical wiring.
Nearly all metals have high melting and boiling points, with some remaining solid even above 2,000°C.
Additional properties of metals include being shiny and sonorous, meaning they produce a ringing sound when struck.

4. Physical Properties of Metals AQA

Metals have metallic bonding, a strong type of bonding unique to metals that is responsible for their characteristic physical properties.
Metals are malleable, meaning they can be bent or hammered into shape without snapping.
Metals are excellent conductors of heat and electricity, which is why they are used in electrical wiring.
Nearly all metals have high melting and boiling points, with some remaining solid even above 2,000°C.
Additional properties of metals include being shiny and sonorous, meaning they produce a ringing sound when struck.

Non-metals tend to be dull in colour and brittle, meaning they break easily (e.g. the carbon in a pencil).
Non-metals generally have low melting and boiling points, and many exist as gases at room temperature.
Non-metals are poor conductors of electricity and typically have lower densities than metals, meaning they weigh less for a given volume.

5. Physical Properties of Non-Metals AQA

Non-metals tend to be dull in colour and brittle, meaning they break easily (e.g. the carbon in a pencil).
Non-metals generally have low melting and boiling points, and many exist as gases at room temperature.
Non-metals are poor conductors of electricity and typically have lower densities than metals, meaning they weigh less for a given volume.

Transition metals are found in the centre block of the periodic table and display all the typical properties of metals described above.
A key feature of transition metals is that they can form more than one type of ion; for example, chromium can form 2+, 3+, and 6+ ions.
Transition metal ions are often coloured in aqueous solution; for example, copper(II) ions are blue, iron(II) ions are green, and chromium(VI) ions are orange.

6. Introduction to Transition Metals AQA

Transition metals are found in the centre block of the periodic table and display all the typical properties of metals described above.
A key feature of transition metals is that they can form more than one type of ion; for example, chromium can form 2+, 3+, and 6+ ions.
Transition metal ions are often coloured in aqueous solution; for example, copper(II) ions are blue, iron(II) ions are green, and chromium(VI) ions are orange.

A catalyst is a substance that increases the rate of a chemical reaction without being used up itself.
Iron acts as a catalyst in the Haber process, which is used to manufacture ammonia.
Nickel is used as a catalyst in the hydrogenation of alkenes, a process used to produce margarine.

7. Transition Metals as Catalysts AQA

A catalyst is a substance that increases the rate of a chemical reaction without being used up itself.
Iron acts as a catalyst in the Haber process, which is used to manufacture ammonia.
Nickel is used as a catalyst in the hydrogenation of alkenes, a process used to produce margarine.