1. Naming Ionic Compounds
Sec. 2.2 Part A
Science 10
Naming Ionic Compounds

2. Review How do atoms form ions? Why do they want to form ions?
What are positively charged ions called? Negatively charged ions?
What can occur once ions have been created?
Why does this occur?

3. Objectives
explain why the IUPAC system of naming compounds is important
describe the process of ionic bonding and give examples of ionic compounds
give correct names and formulas for ionic compounds, using the periodic table, table of ions and IUPAC rules

4. IUPAC and Compound Naming
IUPAC – International Union of Pure and Applied Chemistry
Responsible for naming compounds
Allows consistent way of naming compounds
Why is this important?
Allows for clear and precise communication

5. Simple Ions
In an atom the number of p=number of e which makes it electrically neutral
BUT atoms may lose /gain e in order to have a filled valence level
This makes it stable
Cation = lose electrons
Anions = gains electrons

6. Ionic Compounds How do we form ionic compounds?
Transfer of electrons between atoms
Metals and non-metal
Transfer of electrons creates full outer energy levels
More stable
Attraction of ions called ionic bonding

7. Ionic Compounds
Practice: Give drawings and show electron transfer for the following atoms:
Sodium
Magnesium
Chlorine
Oxygen

8. Naming Ionic Compounds: The Rules
Two part name: cation and anion
1) name cation first with name
2) name anion second with first part of name and change last part to “ide”
Ex. sodium chloride (sodium ion and chloride ion)
IMPORTANT: always write names of elements as lower case (unless at beginning of sentence)

9. Practice
Name the following compounds:
MgO
BaF2(s)
K3N(s)

10. Formulas for Ionic Compounds
Contains element symbols
Some have subscripts
Ex. BaF2(s)
What this means:
One barium ion for every two fluoride ions
Ionic compounds are neutral
Therefore, need to have enough of each atom to cancel the charges out

11. Formulas for Ionic Compounds
What are the charges for each ion in this compound?
Sodium chloride
How many of each ion do we need to cancel the charges out?
How about this one?
Magnesium chloride
How many do we need?
These make the subscripts!

12. Steps for Writing Formulas
Example
Sodium chloride
Aluminium chloride
Identify ions and charges
sodium: Na+
chloride: Cl-
Determine total charges needed to balance
Na+ : 1
Cl- : 1
Note the ratio of cations to anions
1 to 1
Use subscripts to write formula
NaCl
aluminium: Al3+
chloride: Cl-
Al3+ : 3
Cl- : 1+1+1=3
1 to 3
AlCl3
If the ratio is 1:1, do not need to include subscripts
The subscripts should be the simplest form
What does this mean?
Formula unit- name for ionic compound unit (NEUTRAL)

13. Lowest Common Multiple
When charges are not easy to balance:
i.e. calcium nitride
Ca2+ and N3-
Find the lowest common multiple to balance the charges
What is the lowest common multiple here?
Simplify!!! What do you end up with?

14. Balancing Charges
Need to balance the charges i.e. one positive charge balances out one negative charge Why do we need to balance the charges? What happens to our compounds when we do this?

15. Practice Write the formulas/names for the following compounds:
sodium bromide
calcium nitride
magnesium oxide
aluminium chloride
MgS
AlN
Li3P

16. Multivalent Elements Some metals have more than one stable ion
Ex. Iron has two stable ions: Fe2+ and Fe3+.
To indicate which ion it is, use Roman numerals in names
Example: iron (II) or iron (III)
Still use subscripts for compounds- be careful about which ion it is!
Ex. FeBr2 = iron (II) bromide
Ex. FeBr3
Only use Roman numerals when more than one ion (ONLY for transition metals)

17. Practice Write formulas for following:
copper (I) nitride
lead (IV) chloride
nickel (III) oxide
Write the names for the following formulas:
AuN
CrO
TiBr4

18. Practice
CoAs
PtAt4
MnO
PuS2
Bi2S3
Po3N4
Cu2O

19. Naming Ionic and Molecular Compounds
Sec A2.2 Part B
Science 10
Naming Ionic and Molecular Compounds

20. Review How does an ionic compound form?
What name would you give for the following?
MgCl2
LiBr
K3N
FeCl3

21. objectives
predict formulas and write names for ionic compounds with polyatomic ions
describe covalent bonding in molecular compounds
identify diatomic/polyatomic molecular elements
give correct names and formulas for molecular compounds with and without hydrogen using periodic table and IUPAC rules

22. Polyatomic ions
Polyatomic ions- ions made of several non-metallic atoms
Come as one “unit” (consider to be one unit when naming)
List in periodic table of polyatomic ions with symbol and charge
Ending usually “-ate” (more oxygen) or “-ite” (less oxygen)

23. Naming with Polyatomic Ions
Cation + anion
DO NOT change the ending of a polyatomic ion
Practice:
Au(NO3)3(s)
(NH4)3PO4(s)
K2Cr2O7(s)

24. Writing Formulas Same method with exception: Practice:
Subscripts for polyatomic ions placed in brackets
Ex. Fe2(SO4)3
Put 3 outside brackets because there are 3 SO42- for each Fe3+
Practice:
barium hydroxide
iron (III) carbonate
copper (I) permanganate

25. Practice NaClO4 KClO3 CuClO2 sodium phosphate calcium hydroxide
iron (II) carbonate

26. Hydrated Ionic Compounds
Some ionic compounds are only stable if water molecules are found between the ions of their crystal structure
Ex. Na2CO3 10 H2O
Name the ionic part of the structure and the number of water molecules
1 water= monohydrate 6= hexahydrate
2= dehydrate 7= heptahydrate
3= trihydrate 8= octahydrate
4= tetrahydrate 9= nonahydrate
5= pentahydrate 10= decahydrate

27. Practice Na2CO3 10 H20 Na2S2O3 6 H20 magnesium sulfate heptahydrate
Cobalt (II) chloride hexahydrate

28. Molecular Compounds Molecule: two or more non-metal atoms bonding
Can be same or different atoms
Fixed numbers of bonded atoms (unlike ionic compounds: formula unit= part of crystal lattice)

29. Covalent Bonds How molecular compounds bond
Atoms share electrons (no transfer)
Pair of shared electrons makes one covalent bond
Allows outer energy levels to be filled
Can share more than one pair of electrons (double or triple bonds)

30. Molecular Elements Elements that form own molecules (ex. O2)
Diatomic- molecule made of 2 of the same atom
H2, N2, O2, F2, Cl2, Br2, I2.
Polyatomic- More than two of the same atom
O3, P4, S8.
Only appear as these when by themselves
Should memorize these!

31. Naming Molecular Compounds without hydrogen
For binary compounds (two elements)
Use Greek prefixes:
What are they for numbers 1-10?
Indicates how many of each atom
Prefix + first element followed by prefix + second element ending in “-ide”
Ex.
N2O (dinitrogen monoxide)
PBr3 CO
CS2

32. Practice Write the names or formulas for the following: CO2(g) N2O(g)
PCl3(g)
oxygen difluoride
dinitrogen tetrasulfide
sulfur trioxide

33. Naming Molecular Compounds With Hydrogen
Often given names
Ex. “water” official IUPAC name for H2O
Table A2.12 (Be familiar with this chart! Should know the important ones/ones you will see most often)

34. How do we tell the Difference?
Go through difference between ionic and molecular compounds
How do we know which is which and when to use what naming rules?