Question

Write the chemical formula of the following compound in a step-by-step manner –

Potassium dichromate

Answer 1

Write the formula of

Potassium dichromate	Symbol	Valency
Potassium	\[\ce{K}\]	\[\ce{1^{+}}\]
dichromate	\[\ce{Cr2O7}\]	\[\ce{2^{-}}\]

Step I – Write each symbol with its valency.
Positive ion is written first
\[\ce{K}^{1+}\]  \[\ce{[Cr2O7]}^{2-}\]
Step II – Interchange the valencies and ignoring the (+) and (−) signs.

The Formula is \[\ce{K2Cr2O7}\]