1. A systematic method of writing chemical formulas and naming compounds
Nomenclature
A systematic method of writing chemical formulas and naming compounds

2. Chemical symbols Symbols are used to represent elements
Either one capital letter, or a capital letter with a lower case letter
Know names and symbols of elements:
1 – 30, plus
Rb, Cs, Sr, Ba, Ag, Au, Cd, Hg, Pt, Sn, Pb, Br, I, and U

3. Chemical formulas Formulas are used to represent compounds
All formulas have more than one symbol
Two or more capital letters
All chemical names have two words
No need to capitalize words in name

4. I. Binary Ionic nomenclature
Binary = two elements
Ionic means cation and anion
Cations (+ ions) are usually metals
Anions (- ions) are usually nonmetals
Therefore:
Two elements, one metal and one nonmetal

5. a) naming them Mg = magnesium Cl = chlorine, so write “chloride”
Name the metal
Name the nonmetal, changing the ending to “ide”
Example: name MgCl2
Mg = magnesium
Cl = chlorine, so write “chloride”
Name is magnesium chloride

6. Name these NaF Na is sodium F is fluorine, so write fluoride
sodium fluoride
Al2O3
Al is aluminum
O is oxygen, so write oxide
aluminum oxide

7. Name these Ca3P2 Ca is calcium P is phosphorus, so write phosphide
calcium phosphide
K3N
K is potassium
N is nitrogen, so write nitride
potassium nitride

8. Name these BaS Ba is barium S is sulfur, so write sulfide
barium sulfide
SrI2
Sr is strontium
I is iodine, so write iodide
strontium iodide

9. Name these Mg3N2 Mg is magnesium N is nitrogen, so write nitride
Magnesium nitride
BeI2
Be is beryllium
I is iodine, so write iodide
beryllium iodide

10. A systematic method of writing chemical formulas and naming compounds
Nomenclature
A systematic method of writing chemical formulas and naming compounds

11. I. Binary Ionic nomenclature
Binary = two elements
Ionic means cation and anion
Cations (+ ions) are usually metals
Anions (- ions) are usually nonmetals
Therefore:
Two elements, one metal and one nonmetal

12. a) naming them Mg = magnesium Cl = chlorine, so write “chloride”
Name the metal
Name the nonmetal, changing the ending to “ide”
Example: name MgCl2
Mg = magnesium
Cl = chlorine, so write “chloride”
Name is magnesium chloride

13. Name these BaS Ba is barium S is sulfur, so write sulfide
barium sulfide
SrI2
Sr is strontium
I is iodine, so write iodide
strontium iodide

14. b) Writing formulas
Notice: subscripts in the name did not effect the naming of these compounds
So, where do the subscripts come from?
Why are they there?
The subscripts are there to balance charges
**ALL IONIC COMPOUNDS ARE NEUTRAL**
The subscripts tell us how many of each element are present in the finished formula
Example: Al2S3 means 2 aluminums and three sulfurs in one “formula unit”

15. b) Writing formulas Write the symbol for each ion Balance the charges
the element and its charge
Balance the charges
The total (+) charge must equal the total (-) charge
“criss cross”
Re-write the formula without any charges

16. Write the formula for: barium phosphide
barium is Ba, the charge is 2+ (column 2A)
phosphide was phosphorus, so P; charge is 3- (column 5A)
Ba2+P3-
Criss-cross to balance charges (2+ with 3-)
Ba3P2

17. Write the formula for: sodium bromide
Sodium is Na, the charge is 1+ (column 1A)
Bromide was bromine, so Br; charge is 1- (column 7A)
Na+Br-
Charges are already balanced (1+ with 1-)
Re-write as NaBr

18. Write the formula for: calcium iodide
calcium is Ca, the charge is 2+ (column 2A)
iodide was iodine, so I; charge is 1- (column 7A)
Ca2+I-
Criss-cross to balance charges (2+ with -)
Ca1I2
Re-write as CaI2

19. Write the formula for: potassium phosphide
potassium is K, the charge is 1+ (column 1A)
phosphide was phosphorus, so P; charge is 3- (column 5A)
K+P3-
Criss-cross to balance charges (+ with 3-)
K3P1
Re-write as K3P

20. Write the formula for: magnesium oxide
magnesium is Mg, the charge is 2+ (column 2A)
oxide was oxygen, so O; charge is 2- (column 6A)
Mg2+O2-
Charges are already balanced (2+ with 2-)
Re-write as MgO

21. Special case Zinc (Zn) is always a 2+ ion
Silver (Ag) is always a 1+ ion
These must be memorized

22. II. Transition metal ionic nomenclature
Transition metals form several possible cations
Example: manganese (Mn) is found as 2+, 3+, 4+, 5+, 6+ and 7+ ion!
There is no compound just called “manganese oxide” – there are at least four compounds that are different manganese oxides
Different charges result in different subscripts

23. II. Transition metal ionic nomenclature
Iron is commonly found as both Fe2+ and Fe3+
Fe2+ is called iron(II)
Fe3+ is called iron(III)
and,…
Cu+ is called copper(I)
Cu2+ is called copper(II), etc…

24. II. Transition metal ionic nomenclature
Lead (Pb) and tin (Sn) behave like the transition metals, and therefore follow the same rules
Pb2+ is lead(II)
Sn4+ is tin(IV)
Zinc and silver DO NOT follow these rules, because zinc is always Zn2+ and silver is always Ag+

25. a) Writing formulas Follow the same rules as the other ionic compounds
Iron(II) oxide is
Fe2+O2-
Charges balance, so formula is FeO
Iron(III) oxide is
Fe3+O2-
Criss cross to balance charges
Fe2O3

26. Write the formula for: vanadium(III) oxide
vanadium is V, the charge is 3+ (roman numeral III)
oxide was oxygen, so O; charge is 2- (column 6A)
V3+O2-
Criss cross to balance charges (3+ with 2-)
Re-write as V2O3

27. Write the formula for: Cobalt (II) iodide
Cobalt is Co, the charge is 2+ (roman numeral II)
iodide was iodine, so I; charge is 1- (column 7A)
Co2+I-
Criss cross to balance charges (2+ with 1-)
Re-write as CoI2

28. Write the formula for: Lead(IV) sulfide
lead is Pb, the charge is 4+ (roman numeral IV)
sulfide was sulfur, so S; charge is 2- (column 6A)
Pb4+S2-
Criss cross to balance charges (4+ with 2-)
Re-write as Pb2S4
Reduce subscripts!! PbS2

29. b) Writing names Same rules as other ionic compounds, except…
You must write a roman numeral in parentheses after the name of the metal to show what the positive charge on the metal is
Only do this with transition metals
And Pb, Sn
But not Zn, Ag

30. Name these NiCl2 Ni is nickel, and it is a transition metal
Cl is chlorine, so write chloride
nickel( ? ) chloride
But, what is the roman numeral?
Note: uncriss cross subscripts to determine charges
Ni2+Cl-
nickel(II) chloride

31. Name these CuS Cu is copper, and it is a transition metal
S is sulfur, so write sulfide
copper( ? ) sulfide
But, what is the roman numeral?
Note: no subscripts, so charges are balanced
S is always 2-, so the copper in this compound must be 2+ !
copper(II) sulfide

32. Name these Cu3N Cu is copper, and it is a transition metal
N is nitrogen, so write nitride
copper( ? ) nitride
But, what is the roman numeral?
Note: subscripts, so charges are not balanced
copper(I) nitride

33. Name these Co3P2 Co is cobalt, and is a transition metal
P is phosphorus, so write phosphide
cobalt(?) phosphide
But, what is the roman numeral?
Note: un-crisscross subscripts to determine charges
Co2+P3-
cobalt(II) phosphide

34. Name these NO! PbO2 Pb is lead, and it behaves like transition metals
O is oxygen, so write oxide
lead( ? ) oxide
But, what is the roman numeral?
Note: subscripts show charges are not balanced
lead(II) oxide, right?
NO!

35. Name these YES! PbO2 Careful - O is oxide – and is always 2-
So the total (-) charge is 4-!
So, what is the roman numeral?
To balance the 4- charge, you need a 4+ charge
lead(IV) oxide, right?
YES!

36. Be careful… When the charges become subscripts that can be reduced
Examples:
4+/2- SnO2 is tin(IV) oxide
6+/3- CrP2 is chromium(VI) phosphide
6+/2- MnS3 is manganese(VI) sulfide

37. A systematic method of writing chemical formulas and naming compounds
Nomenclature
A systematic method of writing chemical formulas and naming compounds

38. III. Polyatomic Ionic nomenclature
Polyatomic ions are groups of atoms covalently bonded together, that act as a single ion
Think of them as lego blocks that have been glued together
Each have a name and charge that must be memorized

39. Polyatomic ions Nitrate: NO31- bicarbonate: HCO31-
Image source: wikipedia

40. Polyatomic ions carbonate: CO32- acetate: C2H3O21- or CH3COO-
Image source: wikipedia

41. Polyatomic ions 1+ ions Ammonium 1- ions Nitrate Hydroxide Bicarbonate
NH4+
1- ions
Nitrate
NO3-
Hydroxide
OH-
Bicarbonate
HCO3-
Permanganate
MnO4-
Acetate
C2H3O2-

42. Polyatomic ions 2- ions Sulfate Carbonate 3- ions phosphate SO42-
CO32-
3- ions
phosphate
PO43-

43. a) Writing names Same as before: Write the name of the cation
Write the name of the anion
Simply write the polyatomic ion’s name as it is, without any changes
Still only two words in the name

44. NaNO3
More than two capital letters, so there must be at least one polyatomic ion in the formula
Na is sodium, so…
The entire “NO3 part” must have a one word name:
Nitrate is NO3-
sodium nitrate

45. Al2(SO4)3
More than two capital letters, so there must be at least one polyatomic ion in the formula
Al is aluminum, so…
The entire SO4 part must have a one word name:
Sulfate (SO42-)
aluminum sulfate

46. (NH4)3PO4 Obviously more than two elements Look for polyatomic ions
“NH4” is ammonium
“PO4” is phosphate
Ammonium phosphate

47. b) Writing formulas Follow the same rules as the other ionic compounds
Iron(II) sulfate is
Fe2+SO42-
Charges balance, so formula is FeSO4

48. b) Writing formulas Iron(III) sulfate is Fe3+ SO42-
Criss cross to balance charges
But: we don’t want Fe2SO43
There aren’t 43 oxygens!
Use parentheses around polyatomic ion
Fe2 (SO4)3

49. Write the formula for: Chromium(III) carbonate Cr3+ CO32-
Crisscross to balance charges
Cr2(CO3)3

50. Write the formula for: Magnesium hydroxide Mg2+ OH-
Crisscross to balance charges
Mg(OH)2
you need parentheses around the hydroxide because it is a polyatomic ion, even though it has no subscripts of it’s own.

51. Now – the trickiest ones
Name the formula
FeSO4
Iron(IV) sulfate?
No – the subscript 4 is not from balancing charges!
So, how do you know?
Look for subscripts from balancing charges to “uncrisscross”

52. FeSO4
If the 4 were from balancing charges, the formula would have parentheses around the SO – Fe(SO)4
There is no subscript on the Fe – or on the SO4 – from balancing charges
So, the charges are balanced
Use the “SO4” part to determine the charge on the iron – sulfate has a 2- charge
Iron(II) sulfate

53. Must be memorized… Ag+, Zn2+, no roman numeral when naming
Sn, Pb get roman numerals when naming
Cr, Mn, Sn, Pb – the total negative charge must be determined to get the positive charge
Cannot “uncrisscross” these

54. A systematic method of writing chemical formulas and naming compounds
Nomenclature
A systematic method of writing chemical formulas and naming compounds

55. Types of compounds
All compounds are made of two or more elements held together by chemical bonds
Ions of opposite charges are held together by ionic bonds
Ionic bonding is non-directional
There are no “ionic molecules”
Formulas of ionic compounds show the ratio of cation to anion
Ionic compounds only exist in the solid state, in a 3-D crystal lattice

56. Types of compounds
Covalent compounds are made of elements two or more held together by covalent bonds
Covalent bonding is directional
Between two individual atoms
A group of covalently bonded atoms is referred to as a “molecule”
Covalent compounds are also referred to as “molecular” compounds

57. Binary Molecular Nomenclature
Two nonmetals
no charges to balance
multiple subscripts possible
ex: N2O, NO, NO2, N2O4, N2O5

58. Use prefixes to represent subscripts
mono = 1
di = 2
tri = 3
tetra = 4
penta = 5
hexa = 6
hepta = 7
octa = 8
nona = 9
deca = 10

59. NEVER, EVER, EVER, EVER, EVER, EVER, EVER,
USE PREFIXES WITH A METAL!

60. Rules, continued.. Change second name to end in “ide”
do not use prefixes on the first word if the prefix is “mono”
always use prefixes on the second name

61. Examples...
CO2
carbon = first word
subscript = 1, so no prefix
oxide = second word
subscript = 2, so prefix = di
carbon dioxide

62. subscript = 1, so no prefix oxide = second word carbon monoxide
Examples... CO
carbon = first word
subscript = 1, so no prefix
oxide = second word
subscript = 1, so prefix = mono
carbon monoxide

63. Try to name these… N2O4 N2O dinitrogen tetroxide dinitrogen monoxide
dinitrogen pentoxide
N2O
dinitrogen monoxide NO
nitrogen monoxide
NO2
nitrogen dioxide

64. Writing formulas... Dinitrogen tetroxide di = 2, so two nitrogen’s
tetra = 4, so 4 oxygens
N2O4
Note: do NOT reduce subscripts for molecular compounds