4.3 Intermolecular Forces & Metallic Bonding

Group 17 of the Periodic Table contain non-metals that are often referred to as the halogens.

Iodine, I₂, is one of these halogens. At room temperature and pressure it exists as a grey-black solid.

Describe the bonding and forces present in I₂ in the solid state.

The state of the halogens changes down the group, with fluorine being a gas and astatine being a solid.

Explain why the melting point of the halogens increases down the group.

The halogens are all diatomic covalent molecules.

Predict the most probable physical properties shown by all of the elements in Group 17.

[3]

The halogens can also form interhalogen compounds, such as iodine monochloride, ICl.

Predict the state of iodine monochloride at room temperature and pressure, and explain your answer with reference to the intermolecular forces present.

[3]

Describe the bonding in solid sodium.

Potassium has a lower melting point than sodium does.

Explain why.

Magnesium is in the same period as sodium, but has a much higher melting point.

Explain why.

Predict whether magnesium is harder or softer than sodium and explain why.

Copper is a common metal used in wiring.

Explain the electrical conductivity of copper.

Explain why copper is also very malleable.

[2]

Copper is used in alloys such as brass and bronze.

Outline why copper alloys are usually less malleable than pure copper.

Copper is used for water pipes.

Suggest two properties of copper that make it suitable for this use, excluding malleability.