Polyatomic Ions and Related Oxyacids

Polyatomic Ion

• Definition: A polyatomic ion is a group of atoms that stay together and have an overall ionic charge

• Example: NO3-

The “Standard” Polyatomic Ions

• ClO3- chlorate ion

• BrO3 – bromate

ion

• IlO3- iodate ion

• NO3- nitrate ion

• SO4-2 sulphate ion

• CO3-2 carbonate ion

• PO4-3 phosphate ion

All “standard” polyatomic ions end in “ate”

Altering the number of oxygens.

1. If there is one more O than the standard the ion becomes …

per ________ ateExample: ClO4

-

perchlorateNote: the charge does not change

2. If there is one less O than the standard the ion becomes …

________ iteExample: ClO2

-

chloriteNote: the charge does not change

3. If there are two less O than the standard the ion becomes …

hypo ________ iteExample: ClO-

hypochloriteNote: the charge does not change

Oxyacids (__ic acids)

• HClO3 chloric acid

• HBrO3 bromic acid

• HIO3 iodic acid

• HNO3 nitric acid

• H2SO4 sulphuric acid

• H2CO3 carbonic acid

• H3PO4 phosphoric acid

All “standard” oxyacids take the format :

______ ic acid

Changing the number of oxygens in the acid

1. If there is one more O than the standard, the acid becomes …

per ________ ic acidExample: HClO4

perchloric acid

2. If there is one less O than the standard, the acid becomes …

________ ous acidExample: HClO2

chlorous acid

3. If there are two less O than the standard, the acid becomes …

hypo ________ ous acidExample: HClO

hypochlorous acid