NOMENCLATURE (ie naming compounds)

Transcription

1 NOMENCLATURE (ie naming compounds) An ionic compounds (salt) may be any one of thousands of chemical compounds How do chemists describe which salt they are discussing? There is a system that we will follow when writing the names or the formulas for ionic compounds.

2 NOMENCLATURE (ie naming compounds) Let s look at monatomic ions first. Monatomic of course implies ONE atom in this case with a charge. For example: lithium ion = Li + sodium ion = Na + barium ion = Ba 2+

3 NOMENCLATURE (ie naming compounds) Let s look at monatomic ions first. Monatomic of course implies ONE atom in this case with a charge. For example: lithium ion = Li + sodium ion = Na + barium ion = Ba 2+ All cations!

4 NOMENCLATURE (ie naming compounds) Let s look at monatomic ions first. Monatomic of course implies ONE atom in this case with a charge. But for nonmetals: fluorine as an ion becomes = fluoride ion = F - chlorine becomes chloride ion = Cl - oxygen becomes oxide ion = O 2-

5 NOMENCLATURE (ie naming compounds) Let s look at monatomic ions first. Monatomic of course implies ONE atom in this case with a charge. But for nonmetals: fluorine as an ion becomes = fluoride ion = F - chlorine becomes chloride ion = Cl - oxygen becomes oxide ion = O 2- Anions!

6 NOMENCLATURE (ie naming compounds) Let s look at monatomic ions first. Monatomic of course implies ONE atom in this case with a charge. But for nonmetals: fluorine as an ion becomes = fluoride ion = F - chlorine becomes chloride ion = Cl - oxygen becomes oxide ion = O 2- So for nonmetals you drop the ending and replace it with ide. Anions!

7 To write a name for an ionic compound - it is as easy as just writing the names of the ions present. example: NaF is made of the sodium and the fluoride ions.

8 To write a name for an ionic compound - it is as easy as just writing the names of the ions present. example: NaF is made of the sodium and the fluoride ions. becomes known as sodium fluoride

9 To write a name for an ionic compound - it is as easy as just writing the names of the ions present. example: NaF is made of the sodium and the fluoride ions. becomes known as sodium fluoride AlCl3 is made of the aluminum and the chloride ions.

10 To write a name for an ionic compound - it is as easy as just writing the names of the ions present. example: NaF is made of the sodium and the fluoride ions. becomes known as sodium fluoride AlCl3 is made of the aluminum and the chloride ions. becomes known as aluminum chloride

11 Try these two yourself: K2S BaI2

12 Try these two yourself: K2S BaI2 that s potassium sulfide. and that s right this one is barium iodide.

13 But what about these two: CuCl CuCl2

14 But what about these two: CuCl CuCl2 At first glance they both should be copper chloride. They have different formulas so they have to have different names. Right?

15 But what about these two: CuCl CuCl2 Remember from earlier discussions that transition elements can form multiple charges. This means that they can also form multiple compounds with the same anion.

16 But what about these two: CuCl CuCl2 At one time the one on the left was known as cuprous chloride and the one of the right was known as cupric chloride.

17 But what about these two: CuCl CuCl2 But now the one on the left is called copper(i) chloride while the one on the right is called copper (II) chloride.

18 But what about these two: CuCl CuCl2 But now the one on the left is called copper(i) chloride while the one on the right is called copper (II) chloride. copper (I) ion chloride ion copper (II) ion chloride ion Hence the different names.

19 As mentioned you name what you see: FeO Fe2O3

20 As mentioned you name what you see: FeO is iron (II) oxide Fe2O3 is iron (III) oxide

21 As mentioned you name what you see: FeO is made up of Fe 2+ and O 2- Fe2O3 is made up of Fe 3+ and O 2- is iron (II) oxide is iron (III) oxide

22 As mentioned you name what you see: FeO is made up of Fe 2+ and O 2- is iron (II) oxide Fe2O3 is made up of Fe 3+ and O 2- is iron (III) oxide How do we know iron (II) vs. iron (III)? The charge on an oxide ion is ALWAYS 2-. So the example on the left iron has to be 2+ to cancel it out.

23 As mentioned you name what you see: FeO is made up of Fe 2+ and O 2- is iron (II) oxide Fe2O3 is made up of Fe 3+ and O 2- is iron (III) oxide How do we know iron (II) vs. iron (III)? The charge on an oxide ion is ALWAYS 2-. But in the example on the right there are three oxide ions making 6-. So there had to be two iron 3+ to make that one neutral.

24 Try these two yourself: CoCl3 MnO

25 Try these two yourself: CoCl3 Well chloride is ALWAYS 1- and there are three of them so the cobalt had to be 3+. So cobalt (III) chloride. MnO And oxide is ALWAYS 2- and there is only one of them so the manganese had to be 2+. So manganese (II) oxide.

26 So now the charges go: Roman Numerals RN for Sn & Pb

27 Nomenclature YOUR TURN: Write the names for the following ionic compounds: 1. K3N 2. CaBr2 3. Al2S3 4. Na3P 5. RaF2 6. CrO 7. Cr2O3 8. SnCl4 9. BeI2 10. PbO