1. Naming & Formulas: Multivalent & Polyatomic Ions

2. Multivalent Metals Multi = multiple Valent = charge
Metal = specifically transition metals
List all of the possible valencies for the following metals:
Metal
Possible valencies: Cu Fe Pb Mn V Ti Hg Cr Mo W

3. Naming Multivalent Metals
Rule:
Indicate the charge in the name by a roman numeral
Metals are always a positive charge

4. Naming Multivalent Metals
Example 1: CuO
Identify the positive ion and the negative ion
Cu2+ – positive ion (how do we know that it has a charge of 2+?)
O2- – negative ion
What is the name of the positive ion?
Cu2+ - copper (II)
What is the name of the negative ion? – change the ending to “ide”
O2- - oxide
CuO = copper (II) oxide

5. Naming Multivalent Metals
Example 2: Cu2O
Identify the positive ion and the negative ion
Cu+ – positive ion (how do we know that it has a charge of 1+?)
O2- – negative ion
What is the name of the positive ion?
Cu+ - copper (I)
What is the name of the negative ion? – change the ending to “ide”
O2- - oxide
Cu2O = Copper (I) oxide

6. Naming Multivalent Metals
Example 3: PtCl4
Identify the positive ion and the negative ion
Pt4+ – positive ion
Cl- – negative ion
What is the name of the positive ion?
Pt4+ – platinum (IV)
What is the name of the negative ion? – change the ending to “ide”
Cl- - chloride
PtCl4 = platinum (IV) chloride

7. Naming Multivalent Metals

8. Naming Polyatomic Ions
Poly = many
Atomic = atoms
Ions = with charge
*All Polyatomics are listed on the back of your periodic table
Polyatomic Ion
Name
Charge
hydroxide
PO43-
acetate
NO3-
hypochlorite 1+
CrO4 2-
dichromate

9. Naming Polyatomic Ions
Poly = many
Atomic = atoms
Ions = with charge
*All Polyatomics are listed on the back of your periodic table
Polyatomic Ion
Name
Charge
OH-
hydroxide 1-
PO43-
phosphate 3-
CH3COO-
acetate
NO3-
nitrate
ClO-
hypochlorite
NH4+
ammonium 1+
CrO4 2-
chromate 2-
Cr2O7 2-
dichromate

10. Naming Polyatomic Ions
Example 1: NH4Cl
Identify the positive ion and the negative ion
NH4+ – positive ion
Cl- – negative ion
What is the name of the positive ion?
NH4+ – ammonium
What is the name of the negative ion? – change the ending to “ide”
Cl- - chloride
NH4Cl = ammonium chloride

11. Naming Polyatomic Ions
Example 2: KNO3
Identify the positive ion and the negative ion
K+ – positive ion
NO3- – negative ion
What is the name of the positive ion?
K+ – potassium
What is the name of the negative ion? – change the ending to “ide” unless it is a polyatomic ion!
NO3- - nitrate
KNO3 = potassium nitrate

12. Naming Polyatomic Ions
Example 3: Cu(OH)2
Identify the positive ion and the negative ion
Cu2+ – positive ion
OH- – negative ion
What is the name of the positive ion?
Cu2+ – copper (II)
What is the name of the negative ion? – change the ending to “ide” unless it is a polyatomic ion!
OH- - hydroxide
Cu(OH)2 = copper (II) hydroxide

13. Formulas of Polyatomic Ions
Example 1: Magnesium sulphate
What is the charge of magnesium? 2+
What is the charge of sulphate? 2-
To write the formula, we must balance the charges.
Positive
Negative
Mg2+
SO42-
Overall: 2+
Overall: 2-
MgSO4

14. Formulas of Polyatomic Ions
Example 2: Strontium nitrate
What is the charge of strontium? 2+
What is the charge of nitrate? 1-
To write the formula, we must balance the charges.
Positive
Negative
Sr2+
NO3- NO3-
Overall: 2+
Overall: 2-
Sr(NO3)2

15. Formulas of Polyatomic Ions
Example 3: Calcium hydroxide
What is the charge of calcium? 2+
What is the charge of hydroxide? 1-
To write the formula, we must balance the charges.
Positive
Negative
Ca2+
OH- OH-
Overall: 2+
Overall: 2-
Ca(OH)2

16. Naming Polyatomic Ions