Alloys and their properties | Starter Quiz | Oak National Academy

Which of the following best describes an alloy?

• A mixture

• A compound

• An element

• An atom

Answer explanation

An alloy is a mixture of two or more elements, where at least one element is a metal.

Metallic bonding consists of metal ions in a 'sea' of ___.

Answer explanation

Metal atoms lose electrons to form metal ions. These electrons become delocalised and are free to move around the metal. Just saying 'electrons' isn't enough.

Why are pure metals ductile?

• Metal ions are arranged in layers that can slide over one another.

• Delocalised electrons are free to move through the metal.

• Strong electrostatic attraction between metal ions and delocalised electrons.

Answer explanation

In pure metals the metal ions are arranged in layers that can slide over each other when a force is applied.

Is this statement true or false? Pure metals are generally more malleable than their alloy counterparts.

• True

• False

Answer explanation

Pure metals are generally more malleable because they have a more uniform atomic structure, whereas alloys often have added elements that disrupt this structure, making them harder and less malleable.

What is 25% of 50.0? Give your answer to 3 significant figures.

Answer explanation

(25 ÷ 100) × 50.0 = 12.5

Why do metals have high melting points?

• Metal ions are arranged in layers that can slide over one another.

• Delocalised electrons are free to move through the metal.

• Strong electrostatic attraction between metal ions and delocalised electrons.

Answer explanation

The metallic bonding between the metal ions and the delocalised electrons is very strong. Large amounts of energy are needed to overcome the electrostatic attraction.