Question

Write the symbols for the elements present in the compounds:

Sulfur trioxide

Answer 1

To write the formulae of any chemical compound we follow the given steps:

1. Write the symbols for the elements present in the compound
2. Write their respective valencies below the symbols.
3. Using the criss-cross method, assign the second valency to the first element and the first valency to the second element.
4. For complete formula, write the numerals in the subscript of the symbols of elements.

the formula of Sulfur trioxide will be :

Name of elements: Sulfur 3 Oxygen

Symbols of elements: S 3 O

Valency of elements: 6 2

Formula: ${\mathrm{SO}}_3$ ( and not ${\mathrm{S}}_2{\mathrm{O}}_6$ because we have to divide by the common factor 2).