An ionic compound forms when a metal bonds with a non-metallic element. Metals usually form the cation and non-metal anions. Chromium has an oxidation number of +3 in the compound and charge on hydroxide ion is -1.
Cation here is [tex]Cr^{3+}[/tex]
Anion is the hydroxide ion [tex]OH^{-}[/tex]
So the formula of the compound will be: [tex]Cr(OH)_{3}[/tex]. The compound has one chromium atom and two hydroxide ions.
Therefore, there will be one Chromium atom per each chromium hydroxide compound.
