Cr is a transition metal and has a variation of oxidation number from 0 in the elemental state to +6 in the dichromate ion.
+2 for Ca, +6 for Cr, -2 for each O
In CrBr (chromium monobromide) Cr would have an oxidation number of +1. This compound is not known perhaps you meant CrBr3, where chromium has an oxidation number of +3
In Cr2O72- chromium (Cr) has an oxidation number of 6+ while oxygen has an oxidation number of 2-.
As with any other element, the oxidation number of Cr depends on whether and how it is chemically bonded. The oxidation number of pure elements is arbitrarily defined to be 0. In compounds, Cr has oxidation numbers of +2, +3, and +6, depending on the compound.
The answer is +6
+2 for Ca, +6 for Cr, -2 for each O
In CrBr (chromium monobromide) Cr would have an oxidation number of +1. This compound is not known perhaps you meant CrBr3, where chromium has an oxidation number of +3
In Cr2O72- chromium (Cr) has an oxidation number of 6+ while oxygen has an oxidation number of 2-.
As with any other element, the oxidation number of Cr depends on whether and how it is chemically bonded. The oxidation number of pure elements is arbitrarily defined to be 0. In compounds, Cr has oxidation numbers of +2, +3, and +6, depending on the compound.
The answer is +6
+6
+6
+6 for Cr
O.S. of Cr = +6
6+
+6 for Cr, -2 for each O in Cr2O72-
potassium dichromate is K2Cr2O7. The oxidation number of Cr is -6. (Oxygen is -2, K is +1 so Cr must be -6)