Compound Naming

1
Compound Naming Formula Writing
2
Oxidation Numbers

• To fully understand formula writing and compound
  naming, you must first have a basic understanding
  of how to assign oxidation numbers.
• What is an oxidation number?
• Charge on an ion.

3
Oxidation Number Rules

• Hydrogen within compounds is almost always 1.
• Oxygen within compounds is almost always -2.
• In binary ionic compounds the anion (negatively
  charged ion) always has the most common (top)
  charge.
• Group 1 metals are always 1 in a compound Group
  2 metals are always 2 in a compound.

4
Oxidation Rules Continued

• Elements on their own have an oxidation number of
  zero (0).
• Ions have an oxidation number equal to their
  charge.
• The sum of the oxidation numbers within a
  polyatomic ion are equal to the charge of the
  ion.
• The sum of the oxidation numbers within a
  compound must equal zero (0).

5
Assigning Oxidation Numbers

• NH3 SO4-2
• Fe CaCrO4
• Zn(NO3)2 H2S2O3

6
Assigning Oxidation Numbers

• MnCl3 Hg22
• H2Cr2O7 PbO2
• N2O5 C2O4-2

7
Naming Compounds

• There are 3 main categories of compounds
• 1) Binary Ionic
• 2) Ternary Ionic
• 3) Binary Covalent

- All nonmetals
8
Naming Compounds

• There are 3 main categories of compounds
• 1) Binary Ionic
• 2) Ternary Ionic
• 3) Binary Covalent

- Name of metal nonmetal ending in ide.
- Tend to end in ate or ite found on Table E!!!
- Can be named according to stock method, or with
Greek prefixes.
9
Stock Method

• If the first element in the compound has more
  than one (1) charge, you must use a roman numeral
  to specify which charge was used.

10
Naming Compounds
Ca(ClO3)2 BaF2 K3PO4 FeO PbCl4
Cr2O3 AuN CrCO3 Na2S2O3 Zn3N2
11
Writing Rules

• First write out the ions (with charges)
  represented by the name.
• Note always select the top charge of the
  nonmetal for binary ionic compounds.

12
Writing Rules

• Second, check to see if the sum of the charges
  equals zero (keep in mind that compounds have no
  charge!).
• If the sum is zero, then the formula consists of
  a 11 ratio (we dont write the ones).
• Third, if the sum of the charges is not zero, we
  must utilize the Criss-Cross method.

13
Criss-Cross Explained

• Heres an example where the sum of the exponents
  is not zero
• Zinc Nitride

14
Criss-Cross Explained

• Zinc Nitride
• Zn2 N-3

15
Criss-Cross Explained

• Lets watch the criss-cross in action!
• Zn N

2
-3
16
Criss-Cross Explained

• Lets watch the criss-cross in action!
• Zn N

2
3
17
Criss-Cross Explained

• Lets watch the criss-cross in action!
• Zn N

2
3
18
Criss-Cross Explained

• Heres what this means
• Zn N

2
3
19
Criss-CrossThe Final Frontier

• Finally
• You must reduce the subscripts to the lowest
  whole number ratio! (this only applies to
  ionics!)
• For example X2Y4 should become?
• XY2

20
Formula Writing
Potassium Sulfate Lithium Oxide Iron (II)
Sulfide Cobalt (III) Hydroxide
Ammonium Chloride Barium Fluoride Manganese
(II) Phosphate Nickel (III) Nitride
21
Binary Covalent Compounds

• These are compounds that contain 2 different
  nonmetals.
• Naming these and writing formulas are extremely
  straightforward.
• The only challenge is recognizing that this is a
  covalent, not ionic compound.

22
Alas, there is no reference table

• We utilize greek prefixes to indicate the number
  and type of elements present.
• The second element listed ends in ide, just like
  before.
• However, we dont reduce subscripts for covalent
  compounds!!!
• These can also be named using the stock method.

23
And the prefixes are
24
One more thing to keep in mind

• We only use the prefix mono- for the second
  element.
• Example
• CO
• Is not monocarbon monoxide.
• It is carbon monoxide.

25
Naming Examples

• SF6
• P4O10
• P2O5

26
Naming Examples

• NBr3
• Na2S
• SO2

27
Writing Covalent Formulas

• It doesnt get much easier than this.
• Simply convert the prefix into their
  corresponding number.

28
Writing Formula Examples

• Phosphorus trifluoride
• Carbon tetrachloride
• Pentacarbon nonahydride