Third Example
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Third Example

Iron and Bromine

 

Iron is a transition metal.  You should have memorized the charges for copper and iron. Iron has an ion with a +2 charge called iron(II) ion or ferrous ion, and one with a +3 charge called iron(III) ion or ferric ion. Bromine, of course, has a -1 charge and is called bromide ion.

Because there are two types of cations, two different compounds can be formed. When the Fe2+ combines with bromide, you will get FeBr2. FeBr2 is named iron(II) bromide because it is made of iron(II) ions and bromide ions. It can also be called ferrous bromide.

If the iron +3 ion combines with bromide, then that will give you FeBr3 because three bromide ions are needed to neutralize the charge on a +3 ion. FeBr3 is named iron(III) bromide because it is made of iron(III) ions and bromide ions. It can also be called ferric bromide.
Ions

Fe2+
Br-

Fe3+
Charge ratios

2
1

3
1
Ion ratios
1
2
1
3
Formulas FeBr2 FeBr3
Names iron(II) bromide iron(III) bromide

 

 

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