Which of the following metals can be cut with a knife?

[more than one answer]

• sodium

• magnesium

• potassium

• calcium

Which of the following metal is used as flares and camera flushbulbs?

• aluminium

• potassium

• magnesium

• calcium

Which metal is suitable to make the object as in the diagram?

• calcium

• iron

• zinc

• silver

Based on the diagram, the ship's bodies had covered with rust as it was always exposed to air and oxygen. Which of the following can be done to cover the rusting process?

• Use a nitrogen to slow down the chemical reaction

• Coat the bodies with zinc in a process called zinc plating

• Change the bodies by using zinc that does not corrode in the air

• Coat with sulfur as it does not dissolve in water

Why is copper particularly useful in electrical circuits?

• does not corrode in air

• very reactive metal

• a very good conductor of heat

• support burning

Which gases can burn in air?

• oxygen

• hydrogen

• nitrogen

• helium

- a colourless, odourless gas

- does not allow things to burn in it

- slows down the chemical reaction

The features above best describe

• helium

• mercury

• bromine

• nitrogen

Why is helium used in airships?

• It can burn in air

• It is less dense than air

• It does not dissolve in water

• It can conducts electricity

Which of the following are true about bromine?

[more than one answer]

• produce a toxic fumes with an unpleasant smell

• used in making flame retardants

• it is red brown liquid which soluble in water

• it can burns in air to produces oxide

Which metals have the highest density but the lowest melting and boiling point?

• iron

• zinc

• mercury

• silver