1. 2-1 C & D: Names and Formulas of Compounds

2. Ionic Compound Formation
Ionic compounds are made up of positive and negative ions.
All of the positive and negative ions organize in a pattern.
Negative-positive attract.
Negative-negative and positive-positive repel.
Ionic compounds form from the inside out as solid crystals.
Ionic compounds are like a solid stack of bricks.
A salt shaker contains thousands of small pieces of NaCl.

3. Covalent Compound Formation
Covalent molecules share electrons.
There is generally no order to the formation of covalent molecules.
These molecules clump together as solids, liquids or gases.
Covalent molecules are like a play-pit full of plastic balls.
Each plastic ball = 1 covalent molecule of H2O

4. Names & Formulas of Ionic Compounds
Remember: Ionic compounds are composed
of ions (1 positive and 1 negative)
To Name an Ionic Compound:
Name the cation:
- it’s the same as on the periodic table
Name the anion
-drop the end of the element name and add “ide”

5. Examples:
NaCl
KBr
CaF2
4. MgO

6. Ionic Compound Formulas
Symbols represent the elements in the compound
Subscript numbers following the symbol show how many of each element are present.
Example:
Sr3P2
- Contains 3 atoms Sr (strontium) and 2 atoms P (phosphorus)

7. Writing Ionic Compound Formulas
The ion charge shows what ion each element forms to complete their valence shell of electrons
Al has an ion charge of +3, therefore it loses 3 electrons
Br has an ion charge of -1, therefore it gains one electron
For Al and Br to form a compound Al needs to give away 3 electrons and Br needs to accept them.
But wait!!! Br only needs to accept one, so how does this work??

8. Writing Ionic Compound Formulas
Each Br can accept only 1 electron, so 3 Br atoms are needed to combine with 1 Al
The overall formula needs to show this  AlBr3

9. Writing Ionic Compound Formulas
What would the Ionic Formula be for a compound made of Aluminum and Sulphur?
Al has an ion charge of +3
S has an ion charge of -2

10. For all elements to end up with full valence shells, 2 atoms of Al and 3 of S are required.
Formula = Al2S3

11. Shortcut to write the formula:
Write the symbol and ion charge of the cation
Write the symbol and ion charge of the anion
“Swap and drop” the charges and write as subscripts
Reduce numbers (if possible)

12. Examples:
Aluminum sulphide
Al S-2
Al S
Al2S3

13. Examples:
Magnesium Oxide
Mg O-2
Mg O
Mg2O2
REDUCE!!
MgO

14. Practice: Write formulas for the following ionic compounds:
Zn+2 with I-1

15. Practice: Write formulas for the following ionic compounds:
Al+3 with P-3

16. Practice: Write formulas for the following ionic compounds:
Ca+2 with O-2

17. Practice: Write formulas for the following ionic compounds:
Barium phosphide

18. Practice: Write formulas for the following ionic compounds:
Lithium fluoride

19. Practice: Write formulas for the following ionic compounds:
Aluminum nitride

20. Assignment: Complete the practice problems on pages 187 and 188
Complete Nomenclature Packet Worksheet 1

21. Compounds Containing a Multivalent Metal
Multivalent metals have more than one possible ion charge.
The name must indicate which ion charge is used in the formation of the compound
We use roman numerals to indicate ion charge:
I = 1 VI = 6
II = 2 VII = 7
III = 3 VIII = 8
IV = 4 IX = 9
V = 5 X = 10

22. Compounds Containing a Multivalent Metal
Examples:
V4+ = Vanadium (IV)
Ni3+ = Nickel (III)
Writing formulas is identical to other ionic compounds, simply use the roman numeral to determine the ion charge of the cation!

23. Compounds Containing a Multivalent Metal
Example:
Copper (I) nitride

24. Compounds Containing a Multivalent Metal
Example:
Manganese (IV) oxide

25. Compounds Containing a Multivalent Metal
Example:
Chromium (III) bromide

26. Compounds Containing a Multivalent Metal
Naming these types of compounds requires an extra step
I will show you two different methods, the first requires that you must UNCRISSCROSS!!

27. Compounds Containing a Multivalent Metal
Example: Name PdS2
1. Look up the metal on the periodic table and confirm that it is multivalent.
2. Uncrisscross so that the subscripts become charges once again
Pd1S2
Pd2+ S1-

28. Compounds Containing a Multivalent Metal
Check the ion charge of the non-metal to make sure it’s correct. If not, multiply both charges to make it correct.
Pd2+ S1-
- wait!! Sulfur should have an ion charge of -2!!
-to fix this, multiply both ion charges by 2
Pd4+ S2-

29. Compounds Containing a Multivalent Metal
Name the metal, using roman numerals to indicate its ion charge
Palladium (IV)
Name the non-metal, swapping ending for –ide.
Palladium (IV) Sulphide

30. Compounds Containing a Multivalent Metal
The second method uses a “teeter-totter” to figure out the charge of the multivalent metal
Example: Name PdS2

31. Compounds Containing a Multivalent Metal
Practice! Name this compound: SnBr2

32. Compounds Containing a Multivalent Metal
Practice! Name this compound: VCl5

33. Compounds Containing a Multivalent Metal
Practice! Name this compound: Ni2S3

34. A site for extra practice

35. Assignment: Complete the practice problems on pages 190 and 191
Complete Nomenclature Packet Worksheet 2

36. Polyatomic Ions
Some special molecules lose or gain electrons as a group
These ionic molecules are called polyatomic ions

37. Polyatomic Ions
You can recognize that a compound has a polyatomic ion in it because it will be made up of MORE THAN 2 TYPES OF ATOMS!
The name is still made up of ONLY 2 PARTS!
Naming:
Example: NaNO3
Name the cation
Sodium
2. Name the polyatomic ion
Nitrate
Sodium Nitrate

38. Practice:
Name the following compound
K2Cr2O7

39. Practice:
Name the following compound
Fe(OH)3

40. Example: Calcium Bicarbonate
Writing Formulas
Write the symbol and ion charge for both parts of the name
Criss Cross the charges
- put brackets around the polyatomic ion if necessary
3. Reduce if possible
Example: Calcium Bicarbonate
Ca2+ HCO3-
Ca HCO3
Ca(HCO3)2

41. Practice: Write the formula for the following compound
Ammonium chloride

42. Manganese (III) chlorate
Practice:
Write the formula for the following compound
Manganese (III) chlorate

43. Complete the Practice Problems on Page 193
Complete Nomenclature Packet Worksheet #3
Complete Nomenclature Packet Worksheet #4 – Be careful, this one mixes up all the different types of ionic compounds!

44. Binary Covalent Molecules
These are molecules made up of 2 types of non-metals.
The systems for naming and writing formulas for these compounds is very different than the ionic compounds we’ve looked at so far

45. Binary Covalent Molecules
The names of these compounds tell you exactly how many of each atom are present.
There is no need to look up charges or crisscross!!
The Prefixes:

46. Binary Covalent Molecules
Naming Molecules:
Name the left element
Add a prefix in front of the element symbol indicating how many atoms of that element are present (unless there is only one, then don’t use a prefix)
Name the second element
Add a prefix in front of the element symbol indicating how many atoms of the 2nd element are present (use mono as the prefix if there is only one)

47. Examples: CO
N2O3

48. Binary Covalent Molecules
Writing Formulas:
Look at prefix and name of first element. Write the element symbol followed by a subscript number showing how many of that element are present.
Look at prefix and name of second element. Write the element symbol followed by a subscript number showing how many of that element are present.
DO NOT REDUCE!!!!!!!

49. Binary Covalent Molecules
Examples:
Nitrogen tribromide

50. Binary Covalent Molecules
Examples:
Disulfur decafluoride

51. Binary Covalent Molecules
Examples:
Diphosphorus pentoxide

52. Assignment: Complete the practice problems on page 195
Complete Nomenclature Packet Worksheet 5

53. Remember:
You must check to see whether a compound is ionic or covalent so that you know which of the two naming systems to use!
IONIC
COVALENT
Contains a metal and a non-metal.
Contains only non-metals.
Contains a polyatomic ion. You can tell if there’s a polyatomic ion present because the compound will contain more than two types of elements.
Does not contain polyatomic ions.
Might have a Roman numeral in the name.
Never has a Roman numeral in the name.

54. Assignment: Complete Nomenclature Packet Worksheet 6
Be careful, this one mixes up ionic and covalent compounds!