Скачать или смотреть How to find the Oxidation Number for Br in the BrO3- ion. (Bromate ion)

To find the correct oxidation number for Br in BrO3- (the Bromate ion), and each element in the ion, we use a few rules and some simple math.

First, since the Bromate ion has an overall charge of 1- we could say that the oxidation numbers in BrO3- need to add up to charge on the ion.

We write the oxidation number (O.N.) for elements that we know and use these to figure out oxidation number for Br.

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GENERAL RULES
In an ion the all Oxidation numbers must add up tothe charge on the ion.
Group 1 = +1
Group 2 = +2
Hydrogen with Non-Metals = +1
Hydrogen with Metals (or Boron) = -1
Fluorine = -1
Oxygen = -2 (except in H2O2 or with Fluorine)
Group 17(7A) = -1 except with Oxygen and other halogens lower in the group
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We know that Oxygen usually is -2 with a few exceptions. When Oxygen is in a peroxide, like H2O2 (Hydrogen peroxide), it has a charge of -1. When it is bonded to Fluorine (F) it has an oxidation number of +2.

Here it is bonded to Br so the oxidation number on Oxygen is -2. Using this information we can figure out the oxidation number for the element Br in BrO3-.