1. Writing Chemical Formulas and Naming Chemical Compounds

2. Lesson #5 – Naming Metal-Non-Metal Compounds
Words for your glossary:
Chemical Formula
Valence
Binary Compound
Zero Sum Rule
Polyatomic Ion

3. The Language of Chemistry
It’s like learning a new language
You will learn to take the name of a compound and then find it’s formula Eg. Carbon dioxide = CO2
You will also learn to translate a formula into words Eg. MgCl2 becomes magnesium chloride.
There are three main patterns: naming ionic compounds, polyatomic ions, and covalent compounds.

4. Chemical Formulas Provides two important types of information:
1. ________________________________________________________________
2. The number of atoms of each element that are present in a compound.
Tip: __________________________________________________
Eg. Ca + Br (pp.95 in text)

5. What a chemical formula represents
In covalent compounds: how many of each type of atom are in the molecule
Eg. NH3
In Ionic compounds: ______________________________________________
Eg. MgO
Remember that ionic compounds are found in a lattice structure so in MgO, the atoms exist in a 1:1 ratio, held together by ionic bonds.

6. Valence Numbers
Valence: __________________________________________________________________________________________________
Eg. Group 1 elements have the capacity to lose one e- in order to bond. They have a valence of +1.
Some larger elements have 2 or more valence numbers. Table 3.3, pp. 97.

8. Naming Compounds That Contain a Metal and a Nonmetal
Binary ionic compounds contain ___________
_____________________________________
Type I compounds
Metal present forms only one cation
Type II compounds
Metal present can form 2 or more cations with different charges

9. Naming Compounds That Contain a Metal and a Nonmetal

10. Naming Ionic Compounds
Type I Binary Ionic compounds

11. Naming Compounds That Contain a Metal and a Nonmetal
For compounds containing both a metal and a nonmetal, ____________________________The nonmetal is named from the root element name.

12. Cations with 2 or more Valences
Type II Binary Ionic compounds
Since the metal ion can have more than one charge, a ________________________is used to specify the charge.
Outlined in your text as the Stock System (pp.103, table 3.6)

13. Common multi-valent cations
Type II Binary Ionic compounds

14. Polyatomic ions are charged entities composed of several atoms bound together.
They have special names and must be memorized.

15. Polyatomic Ions YOU need to know
Chlorate
Nitrate
Carbonate
Sulfate
Phosphate
Ammonium
Hydroxide

16. Naming ionic compounds containing polyatomic ions follows rules similar to those for binary compounds.
ammonium acetate

17. Polyatomic Ions ____________________________________
“poly” means “many” or “lots” in Greek
__________________________________
Remain unchanged in simple reactions because of _________________________
They behave like a single unit and should be treated as a ______________________
The most common is NH4+ - Ammonium
Table 3.4 pp. 98

18. Writing Chemical Formulas Using Valences
Zero Sum Rule:
Eg. KF = the sum of the valences is O
What if you have compound that has multi-valent ions?

19. Cross-Over Rule
Cross Over Rule lets you balance the equations. Pp.99 in your text.
Let’s take Mg – Cl
1. Write the unbalanced formula (metals first)
2. Add the valence numbers
3. Cross over numbers
4. Check the subscripts (reduce or remove any valences of 1)

21. Practice! Sodium Sulphide Aluminum Sulphide Calcium Oxide
Calcium Phosphide

22. Crossing Over with Polyatomic Ions
Metal + Polyatomic Ion:
Eg. K – PO4 (potassium phosphate)
1. Write unbalanced formula. Put brackets around the polyatomic ion (s)
2. Write in the valences
3. Cross over, write in the subscripts
4. Tidy up: get rid of 1s, if needed, get rid of the brackets.

23. Poly on Poly
Try Ammonium Phosphate!
What about Ammonium Sulphate?

24. Putting it all together
To name a binary compound (2 elements) which is ionic, write the metal first and the non-metal ending in –ide
Eg. Potassium Bromide
If there is an alternate valence, use the stock system when naming the compound.
Eg. Lead (II) oxide (Pb2+ + O)
Conversely, use the cross over rule to find the chemical formula of a compound.

25. One side note…. Naming compounds that contain Hydrogen
Can be the first name / least EN
Eg. HCI – Hydrogen chloride
OR can be more EN
Eg. Sodium hydride or lithium hydride.
Many compounds that contain H are acids. We will discuss this later………..

26. Copy the following table and fill in the correct formula or name for each of the compounds listed:
Al2O3
MgBr2
Potassium oxide
Ag2S
Manganese ( VII) oxide
PbCl2
Calcium oxide
Copper (II) chloride
BaCl2
Ferric Phosphide

27. Lesson #6 – Naming compounds with polyatomic ions

28. Pattern! ClO- : hypochlorate ClO2- : chlorite ClO3- : chlorate
ClO4- : perchlorate
Can YOU see it?

29. Table 3.7 – Meaning of prefixes and suffixes (pp.105)
Prefix and Suffix
Number of oxygen atoms
HYPO ___________________ITE
X -2 OXYGEN ATOMS
___________________ITE
X-1 OXYGEN ATOMS
___________________ATE
X OXYGEN ATOMS
PER ___________________ATE
X+1 OXYGEN ATOMS

30. Really? Yes, Really!

31. Practice, Practice, Practice!!
Let’s do #23 on pp. 105 together!
Make sure you do the homework for these two lessons. The only way to be good at this stuff is to do LOTS of examples!
Pp. 19 in your green book!
Make sure you do your readings for lessons 6&7 for Monday!