Write symbols of the following elements and the radicals obtained from them, and indicate the charge on the radicals.

Mercury, potassium, nitrogen, copper, sulphur, carbon, chlorine, oxygen

Give examples.

A. Positive radicals

B. Basic radicals

C. Composite radicals

D. Metals with variable valency

E. Bivalent acidic radicals

F. Trivalent basic radicals

Write the steps in deducing the chemical formulae of the following compounds.

Sodium sulphate

Write the steps in deducing the chemical formulae of the following compounds.

potassium nitrate

Write the steps in deducing the chemical formulae of the following compounds.

Ferric phosphate