Physical - Metallic bonding

Question 1

Metallic bonding meaning

Answer 1

many electrostatic forces of
attraction between delocalised electrons,

positively charged metal ions arranged in a metallic lattice.

Question 2

Structure

Answer 2

Giant metallic lattice

Question 3

Why can metals conduct electricity when solid and molten?

Answer 3

Metals contain delocalised electrons, which are the mobile
charge carriers which carry the current.

Question 4

Suggest why gaseous metals do not conduct electricity

Answer 4

A sample of gaseous metal contains gaseous metal atoms NOT ions.
There aren’t any delocalised electrons in a gaseous metal –
therefore the cannot conduct electricity.

Question 5

Why are metals ductile?

Answer 5

Layers of metal ions can slide over one another

Question 6

The strength of metallic bonding depends on

Answer 6

the charge density of
the ions

Question 7

Charge density is about

Answer 7

how much charge there is in a given
volume/space

Question 8

The higher the charge density,

Answer 8

the more charge there is in a given
volume/space
- therefore the stronger the attraction between the metal ion and the delocalised electrons

Question 9

The charge density of an ion depends on two factors

Answer 9

1. The charge on the ion – the higher the charge the
   higher the charge density
2. The size of the ion – the smaller the ion the higher the charge density

Question 10

The greater the charge density of a metal ion

Answer 10

The stronger the metallic bonding
= higher the melting point

Question 11

Which has a higher melting point: Sodium or Magnesium (4 marks)

Answer 11

✓ Magnesium ions have a higher charge (2+) than sodium ions
(1+).
✓ Mg ions are smaller than sodium ions.
✓ There is greater the attraction between the Mg ions and
the delocalized electrons, and there are stronger the
metallic bonds.
✓ More energy is required to overcome the forces of
attraction, therefore the melting point is higher.

Question 12

Which group 1 metal has the highest melting point?
Why?

Answer 12

Lithium.
Lithium ions are the smallest of the group one metals, stronger electrostatic
interactions between the positive metal ion and the delocalised electrons.
This means more energy is required to break the bonds, and the melting
point is higher

Question 13

Why are alloys (mixtures of two metals) less malleable than either of the
pure metals?

Answer 13

Having metal cations of different sizes means the regular layers are lost,
and the odd sized atom prevents the easy sliding of layers past each other