(a(i))[1]
State the positive ion with the lowest concentration.
(a(ii))[1]
State the ion that contains an element from Group IV of the Periodic Table.
(b)[2]
Describe a test for sulfate ions. Include the test and the observations.
(c)[1]
Small quantities of ammonium ions and chloride ions are produced in some body cells. State the formula of the compound made from ammonium ions and chloride ions.
(d)[1]
From the list, choose the salt that is insoluble in water. Tick one box.
(e)[2]
predict the hardness of potassium and describe the observations when rubidium reacts with water.
(f)[2]
Sodium reacts with hydrogen to make sodium hydride, NaH. Complete the symbol equation for this reaction: $2\text{Na} + \ldots \rightarrow \ldots\text{NaH}$