write formulas of ionic compounds from ionic charges and oxidation numbers (shown by a Roman numeral), including: (a) the prediction of ionic charge from the position of an element in the Periodic Table (b) recall of the names and formulas for the following ions: \(NO_3^-\), \(CO_3^{2-}\), \(SO_4^{2-}\), \(OH^-\), \(NH_4^+\), \(Zn^{2+}\), \(Ag^+\), \(HCO_3^-\), \(PO_4^{3-}\)

explain, including by use of an equation, the use of chlorine in water purification to include the production of the active species HOCI and CIO\(^-\) which kill bacteria