Metals & Non-Metals

Question 1

Give examples of some metals found in the home.

Answer 1

lead is used on roofs.
Copper water pipes and wiring.
Water tank made of steel coated with zinc.
Taps made of steel coated with chromium.
Stainless steel radiators and cutlery.
Silver or aluminium is used in the manufacture of mirrors.

Question 2

Summarise the properties of metals.

Answer 2

Many metals are shiny, scientists use the word lustrous to describe this property of metals.
Since metals can be stretched we say they are ductile.
Scientists use the word malleable to describe the property of metals that allows them to be beaten into various shapes.
Metals are good conductors of heat, that is, they allow heat to pass through them easily.
Metals are good conductors of electricity, that is, they allow electricity to pass through them easily.
Many metals are strong, the fact that steel is so strong means that it can support a heavy load. Therefore, it can be used for building bridges and for supporting buildings.

Question 3

Do metals tend to lose or gain electrons? Give an example of this.
Do non-metals tend to lose or gain electrons? Give an example of this.

Answer 3

Metals tend to lose electrons, for example, when sodium metal reacts with chlorine gas, each sodium atom loses an electron.
Non-metals tend to gain electrons. For example, when sodium metal reacts with chlorine gas, each chlorine atom gains an electron.

Question 4

Give the formula for losing an electron and gaining an electron

Answer 4

Loses an electron
Na —————————–> Na^+ + electron
Gains an electron
Cl + electron ————————–> Cl^-

Question 5

Metal definition

Answer 5

A metal is an element that tends to form positive ions.

Question 6

Non-metal definition

Answer 6

A non-metal is an element that tends to form negative ions.

Question 7

Alloy definition

Answer 7

An alloy is a mixture of metals

Question 8

List the properties of non-metals.

Answer 8

Many non-metals are gases.
They are not good conductors of heat.
They are not good conductors of electricity.
Non-metals that are solids tend to be brittle, that is, they cannot be hammered into different shapes but shatter instead.

Question 9

List some examples of alloys.

Answer 9

Brass is a mixture of copper and zinc.
Bronze is a mixture of copper and tin.
Steel is a mixture of iron and carbon. (mixture of a metal and non-metal but is counted as an alloy)
Solder is a mixture of iron and carbon.

Question 10

What has been found when alloying one metal with another?

Answer 10

Chemists have found that alloying one metal with another increases the strength of the metal.

Question 11

Why did people stop making coins out of gold and silver?

Answer 11

Silver and gold were not hard enough and the coins gradually wore away.

Question 12

Rusting definition

Answer 12

Rusting is a chemical reaction in which iron is changed into a new substance Rust)

Question 13

What is a chemical name for rust?

Answer 13

The chemical name for rust iron oxide.

Question 14

What is one problem associated with the use of metals?

Answer 14

They tend to corrode.

Question 15

What is the corrosion of iron and steel called?

Answer 15

The corrosion of iron and steel is called rusting.

Question 16

How is the rusting of metals prevented?

Answer 16

Methods of rust prevention involve coating the metal with some material to prevent air and water from coming into contact with the metal surface.

Question 17

What must be present for rusting to occur?

Answer 17

Both oxygen and water must be present for rusting to occur.

Question 18

What are the most common methods of preventing rust? list and explain them.

Answer 18

1. Painting:
   The paint forms a layer over the metal and prevents air and water from coming into contact with the metal. It is used to prevent corrosion of bridges, ships, gates, cars and bicycles.
2. Oiling or greasing:
   It forms a layer over the surface of the metal and prevents air and water from coming into contact with the metal. This is used for the moving of machines, for example, bicycle chains and car engines.
3. Galvanising:
   The object is coated with zinc to prevent the metal from coming into contact with air or water.
   Iron coated zinc is called galvanised iron.
   This is usually used for corrugated iron, wire for fencing, metal buckets and water tanks.

Question 19

What is the easiest way of discovering if something is a metal or non-metal? What is an exception to this?

Answer 19

To find out if they conduct electricity.
Carbon in the form of graphite is an exception to this as it does conduct an electric current. It is present in the ‘lead’ in pencils.