The mass spectrum for silicon is shown. Calculate the $A_r$ of silicon. Give your answer to two decimal places.
Silicon forms a chloride with a low boiling point, and that chloride reacts with water. Write an equation to show the reaction of the chloride with water.
Draw a three-dimensional diagram showing the shape of the chloride. Give the $\text{Cl-Si-Cl}$ bond angle.
Silicon reacts with oxygen to produce a high melting point oxide. Suggest the formula of the oxide. Suggest, in terms of structure, why the oxide has a high melting point whereas the chloride has a low boiling point.
Element A is in the same period as silicon. Element A reacts with dilute nitric acid to form a nitrate. This nitrate breaks down on heating to form an oxide. Write an equation for the decomposition of the nitrate.
The oxide of element A has a high melting point. Suggest the structure and bonding present in the oxide of A.