SPI Chemistry · Metals and Non-Metals
Properties, Reactivity and Alloys
Metals and non-metals differ in how they look, conduct and react; the reactivity series says which metal can push out another; alloys mix metals to get better properties.
Why this matters
Three questions in the bank, one EASY and two MODERATE: the non-metal whose fibres go into bullet-proof vests, which metal strips react in a salt solution drawn in a figure, and the metals in alnico. Each needs one table on this page.
Concept 1 of 3: Properties and uses of metals and non-metals
Most metals are shiny, can be beaten into sheets and drawn into wires, and conduct heat and electricity. Most non-metals are the opposite. A few exceptions are asked again and again, so learn them by name.
Definition
- Metals are lustrous, malleable, ductile and good conductors. They lose electrons to form positive ions, and their oxides are basic (aluminium and zinc oxides are amphoteric: they react with both acids and bases).
- Non-metals are dull and brittle and do not conduct. They gain electrons to form negative ions, and their oxides are acidic or neutral.
- Exceptions: mercury is a liquid metal; bromine is a liquid non-metal; iodine is lustrous; graphite conducts electricity; sodium and potassium are soft enough to cut with a knife.
- Uses of non-metals: sulphur for vulcanising rubber and making sulphuric acid, chlorine to purify water, nitrogen in fertilisers, boron fibres, which are strong and light, in bullet-proof vests and aircraft parts.
| Property | Metals | Non-metals |
|---|---|---|
| Lustre | Shiny | Dull (iodine is the exception) |
| Hammering | Malleable and ductile | Brittle |
| Heat and electricity | Good conductors | Poor conductors (graphite conducts) |
| State at room temperature | Solid (mercury is liquid) | Solid, liquid (bromine) or gas Mercury and bromine are the two liquid elements. |
| Oxides | Basic (some amphoteric) | Acidic or neutral |
| Ions | Lose electrons: positive ions | Gain electrons: negative ions |
Silver and copper are the best conductors; lead and mercury are poor ones for metals.
Practice this conceptself-check · 5 quick reps
The same idea in a practice question:
Practice questionModerate
Example 1 · Metals and Non-Metals · Properties, Reactivity and Alloys
The non-metal fibres which are used to make bullet-proof vest is
Treating every non-metal as dull and non-conducting
Iodine is lustrous and graphite conducts electricity, yet both are non-metals. Learn these exceptions by name.
Calling every metal oxide basic
Aluminium oxide and zinc oxide are amphoteric: they react with acids and with bases. Most other metal oxides are basic.
Concept 2 of 3: The reactivity series and displacement
Metals can be ranked by how eagerly they react. A metal higher in the list can push a lower one out of its salt solution; a lower one can do nothing to a higher one.
Definition
- Most to least reactive: K, Na, Ca, Mg, Al, Zn, Fe, Pb, (H), Cu, Hg, Ag, Au.
- A metal displaces another from its salt solution only if it is higher in the series. A metal cannot displace itself.
- Metals above hydrogen give hydrogen gas with dilute acids; copper, mercury, silver and gold do not.
- Sodium and potassium react so fast with air and water that they are stored under kerosene.
| Metal | Reaction with water | With dilute acid |
|---|---|---|
| Potassium, sodium | Violent with cold water | Violent |
| Calcium | Less violent with cold water | Gives hydrogen |
| Magnesium | Hot water | Gives hydrogen |
| Aluminium, zinc, iron | Steam only | Gives hydrogen Aluminium is above iron: it displaces iron from iron salts. |
| Lead | No reaction | Slowly |
| Copper, mercury, silver, gold | No reaction | No hydrogen |
Higher metal plus salt of a lower metal: reaction. Lower metal plus salt of a higher metal: nothing.
Practice this conceptself-check · 5 quick reps
The same idea in a practice question:
Practice questionEasy
Example 2 · Metals and Non-Metals · Properties, Reactivity and Alloys
In which of the following beakers reaction will take place?
Expecting a metal to react with its own salt
A metal cannot displace itself. An iron strip in iron sulphate solution shows no reaction.
Thinking aluminium is unreactive because it does not rust
Aluminium is above iron and zinc in the series. A thin layer of aluminium oxide on its surface protects it, which is why aluminium objects last.
Concept 3 of 3: Alloys and what they are made of
Pure metals are often too soft, rust too easily or melt too high. Mixing in another metal (or carbon) fixes that. Alloy questions ask what is in an alloy or what it is used for.
Definition
- An alloy is a uniform mixture of a metal with other metals or a non-metal. Its properties differ from those of the pure metals.
- Pure gold (24 carat) is too soft for jewellery; 22 carat gold is mixed with silver or copper.
- An alloy of mercury with another metal is an amalgam.
- Alloys are usually harder, resist corrosion better and often melt lower than their metals.
| Alloy | Made of | Used for |
|---|---|---|
| Brass | Copper and zinc | Utensils, taps and fittings |
| Bronze | Copper and tin | Statues and medals |
| Solder | Lead and tin | Joining electric wires (low melting point) |
| Stainless steel | Iron, chromium, nickel and carbon | Utensils that do not rust |
| Duralumin | Aluminium, copper, magnesium and manganese | Aircraft bodies |
| Alnico | Iron with aluminium, nickel and cobalt | Strong permanent magnets The name is Al + Ni + Co. |
| Amalgam | Mercury and another metal | Dental fillings |
Brass has zinc, bronze has tin: both start from copper.
Practice this conceptself-check · 4 quick reps
The same idea in a practice question:
Practice questionModerate
Example 3 · Metals and Non-Metals · Properties, Reactivity and Alloys
What are the constituents of Alnico?
Swapping brass and bronze
Brass is copper and zinc. Bronze is copper and tin.
Thinking an alloy behaves like its metals
An alloy's properties are its own. Solder melts lower than lead or tin, and stainless steel resists rust although iron rusts.
Summary — formulas & gotchas at a glance
A revision cheat-sheet for the formulas and gotchas above. Click any concept name to jump back to its full explanation.
Reference tables (3)
Properties and uses of metals and non-metals6 rows
| Property | Metals | Non-metals |
|---|---|---|
| Lustre | Shiny | Dull (iodine is the exception) |
| Hammering | Malleable and ductile | Brittle |
| Heat and electricity | Good conductors | Poor conductors (graphite conducts) |
| State at room temperature | Solid (mercury is liquid) | Solid, liquid (bromine) or gas Mercury and bromine are the two liquid elements. |
| Oxides | Basic (some amphoteric) | Acidic or neutral |
| Ions | Lose electrons: positive ions | Gain electrons: negative ions |
Silver and copper are the best conductors; lead and mercury are poor ones for metals.
The reactivity series and displacement6 rows
| Metal | Reaction with water | With dilute acid |
|---|---|---|
| Potassium, sodium | Violent with cold water | Violent |
| Calcium | Less violent with cold water | Gives hydrogen |
| Magnesium | Hot water | Gives hydrogen |
| Aluminium, zinc, iron | Steam only | Gives hydrogen Aluminium is above iron: it displaces iron from iron salts. |
| Lead | No reaction | Slowly |
| Copper, mercury, silver, gold | No reaction | No hydrogen |
Higher metal plus salt of a lower metal: reaction. Lower metal plus salt of a higher metal: nothing.
Alloys and what they are made of7 rows
| Alloy | Made of | Used for |
|---|---|---|
| Brass | Copper and zinc | Utensils, taps and fittings |
| Bronze | Copper and tin | Statues and medals |
| Solder | Lead and tin | Joining electric wires (low melting point) |
| Stainless steel | Iron, chromium, nickel and carbon | Utensils that do not rust |
| Duralumin | Aluminium, copper, magnesium and manganese | Aircraft bodies |
| Alnico | Iron with aluminium, nickel and cobalt | Strong permanent magnets The name is Al + Ni + Co. |
| Amalgam | Mercury and another metal | Dental fillings |
Brass has zinc, bronze has tin: both start from copper.
Watch out for (6)
- Treating every non-metal as dull and non-conducting→ Properties and uses of metals and non-metals
- Calling every metal oxide basic→ Properties and uses of metals and non-metals
- Expecting a metal to react with its own salt→ The reactivity series and displacement
- Thinking aluminium is unreactive because it does not rust→ The reactivity series and displacement
- Swapping brass and bronze→ Alloys and what they are made of
- Thinking an alloy behaves like its metals→ Alloys and what they are made of
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