Potassium chloride (KCl\text{KCl}KCl) and silicon (Si\text{Si}Si) both have giant structures.
Potassium chloride is an ionic compound.
Silicon is a giant covalent element.
The table shows some properties of each substance:
| Potassium chloride | Silicon |
|---|---|
| Melting point = 770∘C770^\circ\text{C}770∘C | Melting point = 1414∘C1414^\circ\text{C}1414∘C |
| Soluble in water | Insoluble in water |
| Conducts electricity when molten | Does not conduct electricity when molten |
Explain why silicon has a high melting point.
Suggest why the melting point of silicon is higher than the melting point of potassium chloride.
State why potassium chloride conducts electricity when molten.
Nitrogen (N2\text{N}_2N2) is described as a simple molecular substance.
State why nitrogen is a gas at room temperature.
