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Chapter : 3. Atoms & Molecules
Rules for writing a chemical formula
Rules for writing a chemical formula We first write the symbols of the elements which form the compound Below the symbol of each element, we write down its valency. Finally, we cross-over the valencies of the combining atoms. That is, with first atom we write the valency of second atom (as a subscript); and with the second atom we write the valency of first atom (as subscript). Example.