1. Polyatomic ions & Naming ionic Compounds
Unit 5: Chapter 6.3a

2. Bonding Review Ionic - electron transfer
Forms between a metal and a nonmetal
Metals have low electronegativity
Nonmetals have high electronegativity
The metal gives up the electrons and the nonmetal takes them
Covalent - electron sharing
Forms most often between two nonmetals
Electron shared pairs are formed to allow both elements to fulfill the octet rule.

3. Describing Ionic Compounds
These objects are coated with compounds of copper and oxygen. Based on the two colors of the coatings, copper and oxygen must form at least two compounds. So there must also be different ways of naming them.

4. Describing Ionic Compounds
What information do the name and formula of an ionic compound provide?
The name distinguishes the compound from other ionic compounds containing the same elements.
The formula of an ionic compound describes the ratio of the ions in the compound.

5. Binary Ionic Compounds
A compound made from only two elements is a binary compound.
Naming binary ionic compounds is easy. The names have a predictable pattern:
the name of the cation (metal) followed by the name of the anion (nonmetal).
Examples:
Na+ + Cl-  Sodium Ion + Chloride =
Sodium Chloride
K+ + O2-  Potassium Ion + Oxide =
Potassium Oxide

6. Common Anions This table lists eight common anions.
The name of an anion is formed by adding the suffix –ide to the stem of the nonmetal name.

7. Naming Binary Ionic Compounds
Cations (metal) first, then Anion (non-metal)
Cation (metal) name is normal
Example: sodium
Anion (nonmetal) add “ide” suffix
Example: chlorine  chloride
NaCl  sodium chloride
KBr  potassium bromide

8. Polyvalent Metals Many transition metals have “multiple personalities”
# of valence electrons varies
they can form more than one ion (more than one charge).
Also known as valence # or oxidation #
Roman Numerals are used to signify the charge (or how many electrons the metal is lending)
Where are the transition metals located on the periodic table?

9. Transition Metals

10. Polyvalent Transition Metals
Metals with more than one possible charge:
Specific charge is indicated in parenthesis

11. Polyvalent Metals & Bonding
Fe(II) = Fe2+
Iron (II) + oxygen = Iron (II) Oxide
Fe2+ & O2-  FeO
Fe(III) = Fe3+
Iron (III) + oxygen = Iron (III) Oxide
Fe3+ & O2-  Fe2O3
Name these compounds just like other binary ionic compounds but include the metal’s oxidation # in parentheses

12. Polyatomic Ions
Polyatomic Ion - A covalently bonded group of atoms that acts as a unit and has its own charge.
Most simple polyatomic ions are anions.
MUST keep the atoms together
CANNOT change anything about a polyatomic ion
Not the type of atoms
Not the number of atoms
Not the electric charge
How are you going to remember this????
Anytime you see a Polyatomic Ion
PUT IT IN PARENTHESIS!!!

13. Polyatomic Ions

14. Polyatomic Ions & Bonding
Bonding works the same way as it did for binary compounds.
Treat the polyatomic ion as a single entity (a single element)
The criss cross method is the most useful, efficient, and effective way for bonding with polyatomic ions.

15. Criss Cross Method Review
Determine the charges/oxidation #’s for each element.
By criss crossing the charges of the elements you can easily write the chemical formula
Example: Hydrogen + Oxygen
H O–2
Criss cross the oxidation #
just the numbers - not the + / - signs
Write the numbers as subscripts
bottom right of symbol

16. Criss Cross Method Review
Criss Cross the numbers
H2O1
Final: H2O
Where is the 1 in the final formula?
Just like in math, the 1 is always understood.

17. Criss Cross & Polyatomic Ions
Sodium + Sulfate
Na + SO4
Na+1 + (SO4)-2
Do the Criss Cross
Na2(SO4)1
Final: Na2(SO4) or Na2SO4

18. You Try
Magnesium + Sulfate
Mg + SO4

19. You Try
Magnesium + Sulfate
Mg + SO4
Mg+2 + (SO4)-2

20. You Try Magnesium + Sulfate Mg + SO4 Mg+2 + (SO4)-2 Criss Cross
Final: Mg(SO4) or MgSO4
Remember the ratio can be reduced! (the 2’s reduce to 1:1)

21. You Try
Beryllium + Phosphate
Be + PO4

22. You Try
Beryllium + Phosphate
Be + PO4
Be+2 + (PO4)-3

23. You Try Beryllium + Phosphate Be + PO4 Be+2 + (PO4)-3 Criss Cross
Note that the criss cross puts the subscript 2 OUTSIDE of the parenthesis, showing that there are TWO phosphate ions

24. Common Ions Which of these are: Metals? Nonmetals? Transition metals?
Hydrogen H+1
Aluminum Al+3
Nitrate (NO3)-1
Calcium Ca+2
Iron (III) Fe+3
Sulfate (SO4)-2
Zinc Zn+2
Chlorine Cl-1
Carbonate (CO3)-2
Copper (II) Cu+2
Hydroxide OH-1
Phosphate (PO4)-3
Silver Ag+1
Phosphide P-3
Acetate (C2H3O2)-1
Which of these are:
Metals?
Nonmetals?
Transition metals?
Polyatomic ions?

25. Naming with Polyatomic Ions
Compounds containing polyatomic Ions always have IONIC bonds.
Naming these compounds is much like naming binary ionic compounds
List the cation (metal) first
Then the polyatomic ion (most are anions so this follows the binary format)
Use the normal name for the cation (metal) and the given name for the polyatomic ion
Na(OH) or NaOH = Sodium Hydroxide

26. Formulas & Names Use a compound’s formula to determine its name
Na2O  Sodium Oxide
CuF2  Copper (II) Fluoride
K2(CO3)  Potassium Carbonate
Use a compound’s name to determine its formula
Lithium Bromide  LiBr
Iron (III) Oxide  Fe2O3
Aluminum Phosphate  Al(PO4) or AlPO4
You must be able to go back and forth!

27. You Try Write the formula for Calcium Chloride Calcium Oxide
Copper (II) Nitride
Magnesium Sulfate
Give the name for the following compounds
KBr
BeS
PbO2
CsMnO4

28. You Try Write the formula for Calcium Chloride  CaCl2
Calcium Oxide  CaO
Copper (II) Nitride  Cu3N2
Magnesium Sulfate  MgSO4
Give the name for the following compounds
KBr  Potassium Bromide
BeS  Beryllium Sulfide
PbO2  Lead (IV) Oxide
CsMnO4  Cesium Permanganate