Metallic Bonding (properties)

Question 1

Why are metals good conductors of heat and electricity?

Answer 1

The delocalised electrons carry electrical current and thermal (heat) energy through the whole structure, so metals good conductors of electricity and heat.

Question 2

Why are most metals mallable

Answer 2

The layers of atoms in a metal can slide over each other, making metals malleable - this means that they can be bent or hammed or rolled into flat sheets.

Question 3

What are the reasons for alloys being harder than pure metals

Answer 3

• Pure metals often aren’t quite right for certain jobs - they’re often too soft when they’re pure so are mixed with other metals to make them harder. Alloys are a mixture of two or more metals or a a metal and another element. Alloys are harder and so more useful than pure metals so this the reason why most of the metals we use in everyday life are alloys.
• Different elements have different sized atoms. So when another element is mixed with a pure metal the new metal atoms will distort the layers of metal atoms, making it more difficult for them to slide over each other. This makes alloys harder than pure metals.

Question 4

Why are most metals solid at room temperature?

Answer 4

The electrostatic forces between the metal atoms and the delocalised sea of electrons are very strong, so need lots of energy to be broken. This means that most compounds with metallic bonds have very high melting and boiling points, they are generally solid at room temperature.

Question 5

How are metallic bonds formed

Answer 5

1) Metals also consist of a giant structure.
2) The electrons in the outer shell of the metal atoms are delocalised (free to move around). There are strong forces of electrostatic attraction between the positive metal ions and the shared negative electrons.
3) These forces of attraction hold the atoms together in a regular structure and are known as metallic bonding. Metallic bonding is very strong.
4) Substances that are held together by metallic bonding include metallic elements and alloys.
5) It’s the delocalised electrons in the metallic bonds which produce all the properties of metals.