Polyatomic Ion - a group of covalently bonded atoms that have an overall electric charge. They act like a single ion when combining with other atoms to form compounds.

The Lewis structure above shows a group of 5 atoms sharing electrons (covalently bonded) to reach 8 valence electrons. There are a total of 32 valence electrons in the diagram.

• An oxygen atom is known to have 6 valence electrons - 4 X 6 = 24
• A phosphorus atom is known to have 5 valence electrons - 1 X 5 = 5
• That's a total of 29 electrons!
• The group of atoms has 3 EXTRA electrons!

 

See a chart of the polyatomic ions used in this class.

 

Chemical Bonding