1. Naming and Formula Writing
IONIC COMPOUNDS
Naming and Formula Writing

2. Predicting Charges on Monatomic Ions
KNOW THESE !!!!
Cd+2

3. Naming Positive Ions
Before you name an Ion you have to know the charge.
Group 1 = always +1
Group 2 = always +2
Aluminum = always +3
Zinc and Cadmium = always +2
Silver = always +1

4. The Other Metals
All other metals can have various positive charges from +1 to +7
Roman Numerals are used to tell the charge

5. Monatomic Ions

6. Naming Postive Ions
With group 1, 2, Al, Zn, Cd, and Ag you just give the name of the atom
Na+ is Sodium
Mg+2 is Magnesium
Ag+ is Silver
Al+3 is Aluminum

7. All the other metals
With all other metals you give the name Metal followed by a roman numerial
Cu+ - Copper (I)
Cu+2 – Copper (II)
Fe+2 – Iron (II)
Fe+3 – Iron (III)
U+6 – Uranium (VI)

8. Naming negative ions
All negative ions have their endings changed to –ide
Oxygen becomes oxide
Fluorine becomes Fluoride
Nitrogen becomes Nitride
Chlorine becomes Chloride

9. Names of other Negative Ions
Carbide = what you want your parents to do for you
Boride = what happened at the rodeo
Silicide = what you are seeing right now
Fluoride = a state in the union
Iodide = Very sad, I guess we will have to Barium.

10. Writing a Formula
Write the formula for the ionic compound that will form between Ba2+ and Cl.
To cancel out Ba’s +2, then two -1 Cl’s are needed.
Solution:
1. Balance charge with + and – ions
2. Write the positive ion of metal first, and the
negative ion Ba Cl Cl
3. Write the number of ions needed as
subscripts BaCl2

11. Balancing a formula by math
Every ionic compound should have a formula that has a charge that equals zero.
Barium Fluoride
Ba+2 F-
How many F’s are needed to balance Ba+2 ?
Two
Formula is BaF2

12. Another way – Drop, Swap, Reduce
Aluminum Oxide
Al is always +3
Oxide is always -2
Al+3, O-2
DROP: Al3O2
SWAP: Al2O3
REDUCE: 2 and 3 are lowest integers, so leave alone

13. Another example Magnesium Oxide Mg is +2 Oxide is -2 Mg+2, O-2
DROP: Mg2O2
SWAP: Mg2O2
REDUCE: MgO, 2 and 2 divide each other out.

14. Learning Check
Write the correct formula for the compounds containing the following ions:
1. Na+, S2-
a) NaS b) Na2S c) NaS2
2. Al3+, Cl-
a) AlCl3 b) AlCl c) Al3Cl
3. Mg2+, N3-
a) MgN b) Mg2N3 c) Mg3N2

15. Solution 1. Na+, S2- b) Na2S 2. Al3+, Cl- a) AlCl3 3. Mg2+, N3-
c) Mg3N2

16. CaCl2 = calcium chloride
Naming Compounds
Binary Ionic Compounds:
1. Cation first, then anion
2. Monatomic cation = name of the element
Ca2+ = calcium ion
3. Monatomic anion = root + -ide
Cl- = chloride
CaCl2 = calcium chloride

17. Naming Binary Ionic Compounds
Examples:
NaCl
ZnI2
Al2O3
sodium chloride
zinc iodide
aluminum oxide

18. Learning Check Complete the names of the following binary compounds:
Na3N sodium ________________
KBr potassium ________________
Al2O3 aluminum ________________
MgS _________________________

19. Transition Metals
Elements that can have more than one possible charge MUST have a Roman Numeral to indicate the charge on the individual ion.
1+ or or 3+
Cu+, Cu Fe2+, Fe3+
copper(I) ion iron(II) ion
copper (II) ion iron(III) ion

20. Learning Check
Complete the names of the following binary compounds with variable metal ions:
FeBr2 iron (_____) bromide
CuCl copper (_____) chloride
SnO2 ___(_____ ) ______________
Fe2O3 ________________________
Hg2S ________________________

21. Polyatomic Ions Some ions are composed of more than one atom.
These are called polyatomic ions
Poly = more

22. Formulas and names Nitrate = NO3- Sulfate = SO4-2 Silver nitrate
Ag+ NO3-
DSR = AgNO3
Copper (I) Sulfate
Cu+ SO4-2
Cu2SO4

23. More Polyatomics Lead (IV) Phosphate
Pb+4 PO4-3
Pb3(PO4)4
Notice: When more than one Polyatomic is present you surround it with ()
Big: The subscripts on Polyatomic ions are NEVER changed.

24. Learning Check
Write the correct formula for the compounds containing the following ions:
1. Na+, PO4-3
a) NaPO4 b) Na2PO4 c) Na3PO4
2. Al3+, NO3-
a) Al(NO3)3 b) AlNO3 c) Al3NO3
3. NH4+, N3-
a) NH4N b) NH4N c) (NH4)3N

25. Answers 1. Na+, PO4-3 c) Na3PO4 2. Al3+, NO3- 3. NH4+, N3- a) Al(NO3)3
c) (NH4)3N

26. More on Polyatomics Most polyatomic ions end in –ate.
The ending –ite means one less oxygen is present then in the ending –ate.
Example: Nitrate versus Nitrite:
NO NO2-
NOTICE: Only the number of O’s changed, not the charge.

27. Even More
The Prefix Hypo means two less oxygen’s are present then in –ate.
Example: Hyposulfite: SO2-2
The Prefix Per- means one extra oxygen is present then in –ate.
Examples:
Perchlorate ClO4-
Chlorate ClO3-
Chlorite ClO2-
HypoChlorite ClO-

28. Properties of Ionic Compounds
Ionic compounds are:
also known as salts
They are usually hard and brittle
Conduct electricity when molten or dissolved
Have very high melting and boiling points
Most are soluble in water
Normally composed of at least one metal and one nonmetal