polyatomic ions
Post on 16-May-2015
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What are POLYATOMIC IONS?
What are POLYATOMIC IONS?
What is a group of atoms with charge?
back tonaming
compounds
Lets first review what a monatomic ion is
In a single atom (monatomic), charge resultsfrom having either more electrons
or less electrons than protons.
++ +
++
Less electrons than protons= positive charge (cations)
More electrons than protons= negative charge (anions)
++ +
++
Example: The magnesium ion has two
less electrons than protons
Mg
2+
Example: The magnesium ion has two
less electrons than protons
Mg
2+ back topolyatomic
ions
NO
O
O
NO
O
O
In a polyatomic ion, two or more atoms covalently bonded together.
Together, they carry a charge
NO
O
O
1–
The nitrate ion(NO3
–) has, in total,one more electronthan protons
NO
O
O
1–
When balancing charges in an ionic compound,the polyatomic ion acts as a single unit of charge:
Mg(NO3)2
Mg
2+
NO
O
O1-
NO
O
O
1-
NO
O
O
MgNO
O
O2+ 1-1-
2+Mg(NO3)2
NO
O
O
MgNO
O
O2+ 1-1-
2+ 2-the charges are balancedMg(NO3)2
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