1. Unit 5 “Chemical Names and Formulas”
H2O
Unit 5 “Chemical Names and Formulas”

2. Section 9.1 Naming Ions

3. Atoms and Ions Atoms are electrically neutral.
Same number of p+ and e-
Ions - atoms with a charge (+ or -)
Made by gaining or losing electrons.
Only electrons can move

4. F1- O2- An Anion is… A negative ion = gained electrons.
Nonmetals gain electrons.
Charge is written as a superscript on the right.
F1-
Has gained one electron (-ide is new ending = fluoride)
O2-
Gained two electrons (oxide)

5. K1+ Ca2+ A Cation is… A positive ion = losing electrons.
Metals lose electrons
K1+
Has lost one electron (no name change for positive ions)
More protons than electrons
Ca2+
Has lost two electrons

6. Predicting Ionic Charges
Group 1A:
Lose 1 electron to form 1+ ions
H1+
Li1+
Na1+
K1+
Rb1+

7. Predicting Ionic Charges
Group 2A:
Loses 2 electrons to form 2+ ions
Be2+
Mg2+
Ca2+
Sr2+
Ba2+

8. Predicting Ionic Charges
Loses 3 electrons to form
3+ ions
Group 3A:
B3+
Al3+
Ga3+

9. Predicting Ionic Charges
Neither! Group 4A elements rarely form ions (they tend to share)
Group 4A: Do they lose 4 electrons or gain 4 electrons?

10. Predicting Ionic Charges
Nitride
Gains 3
electrons to form
3- ions
Group 5A:
P3-
Phosphide
As3-
Arsenide

11. Predicting Ionic Charges
Oxide
Gains 2 electrons to form 2- ions
Group 6A:
S2-
Sulfide
Se2-
Selenide

12. Predicting Ionic Charges
Gains 1 electron to form 1- ions
Group 7A:
F1-
Fluoride
Br1-
Bromide
Cl1-
Chloride
I1-
Iodide

13. Predicting Ionic Charges
Group 8A: Stable noble gases do not form ions!

14. Predicting Ionic Charges
Group B elements: Many transition elements
have more than one possible charge.
Use of Roman numerals to show charges
Iron (II) = Fe2+
Iron (III) = Fe3+
Show roman numerals up to 5.

15. Naming Cations
Stock system – use roman numerals in parenthesis to indicate the charge value
2. Classical method – uses root word with suffixes (-ous, -ic)
Does not give true value

16. Naming cations
If the charge is always the same (like in the Group A metals) just write the name of the metal.
Calcium = 𝐶𝑎 +2
Transition metals can have more than one type of charge.
Indicate charge as roman numeral in parenthesis after the name of the metal (Table 9.2, p.255)
Iron (IV) = 𝑭𝒆 +𝟒

17. Predicting Ionic Charges
Some post-transition elements also
have more than one possible charge.
Tin (II) = Sn2+
Lead (II) = Pb2+
Tin (IV) = Sn4+
Lead (IV) = Pb 4+

18. Predicting Ionic Charges
Group B elements:
Some transition elements
have only one possible oxidation state, such as these three:
**Do not use roman numerals for these
Silver = Ag1+
Zinc = Zn2+
Cadmium = Cd2+

19. Practice by naming these:
Ca2+
Al3+
Fe3+
Fe2+
Pb2+
Li+
Sodium
Calcium
Aluminum
Iron (III)
Iron (II)
Lead (II)
Lithium

20. Write symbols for these:
Potassium ion
Magnesium ion
Copper (II) ion
Chromium (IV) ion
Barium ion
Mercury (II) ion
𝐾 +
𝑀𝑔 +2
𝐶𝑢 +2
𝐶𝑟 +4
𝐵𝑎 +2
𝐻𝑔 +2

21. Anions are always the same charge Change the ending to –ide
Naming Anions
Anions are always the same charge
Change the ending to –ide
F1- a Fluorine atom will become a Fluoride ion.

22. Practice by naming these:
Cl-
N3-
Br-
O2-
Ga3+
𝐶ℎ𝑙𝑜𝑟𝑖𝑑𝑒
𝑁𝑖𝑡𝑟𝑖𝑑𝑒
𝐵𝑟𝑜𝑚𝑖𝑑𝑒
𝑂𝑥𝑖𝑑𝑒
𝐺𝑎𝑙𝑙𝑖𝑢𝑚

23. Write symbols for these:
Sulfide ion
Iodide ion
Phosphide ion
Strontium ion
𝑆 −2
𝐼 −
𝑃 −3
𝑆𝑟 +2

24. Polyatomic ions are…
Groups of atoms that stay together, have an overall charge, and one name.
Usually end in –ate or -ite
Acetate: C2H3O2-
Nitrate: NO3-
Nitrite: NO2-
Permanganate: MnO4-
Hydroxide: OH- and Cyanide: CN-?

25. Know Table 9.3 on page 257 Sulfate: SO42- Phosphate: PO43-
Sulfite: SO32-
Carbonate: CO32-
Chromate: CrO42-
Dichromate: Cr2O72-
Phosphate: PO43-
Phosphite: PO33-
Ammonium: NH41+
(One of the few positive polyatomic ions)

26. H + Polyatomic ion =….
If the polyatomic ion begins with H, then put “hydrogen” in front of the polyatomic ion: H CO32- → H2CO3 hydrogen + carbonate → hydrogen carbonate ion
H2SO3
H3PO4
HNO3
Hydrogen Sulfite
Hydrogen Phosphate
Hydrogen Nitrate

27. Helpful Hints on Oxy-Anions
1. _________: smaller # of oxygen
2. _________: larger # of oxygen
Ex.
NO3- ____________________________
NO2- ____________________________
SO42- ____________________________
SO32- ____________________________
-ite
-ate
Nitrate
Nitrite
Sulfate
Sulfite

28. A Guide to Determine Whether the –ate Formula is –XO3 or –XO4:1 2 3 4 5 6 13 14 15 16 17 18
Transition Metals B C N Si P S Cl As Se Br I

29. A Guide to Determine What the Charge of the Oxy-Anion is:1 2 3 4 5 6 13 14 15 16 17 18
Transition Metals -3 -2 -1 B C N
- 4 -3 -2 -1 Si P S Cl -3 -2 -1 As Se Br -1 I

30. Section 9.2 Naming and Writing Formulas for Ionic Compounds

31. Writing Ionic Compound Formulas
Example: Iron (III) chloride
Fe3+
Cl-
1. Write the cation and anion with CHARGES! 3
Not balanced!
Now balanced.
2. Balance charges using the criss-cross method with subscripts, if necessary. Use parentheses if you need more than one of a polyatomic ion to balance subscripts.
= FeCl3

32. Writing Ionic Compound Formulas
Example: Aluminum sulfide
Al3+
S2- 2 3
1. Write the cation and anion with CHARGES!
Not balanced!
Now balanced.
2. Balance charges using the criss-cross method with subscripts, if necessary. Use parentheses if you need more than one of a polyatomic ion to balance subscripts.
= Al2S3

33. Writing Ionic Compound Formulas
Example: Zinc hydroxide
Zn2+
( )
OH-
1. Write the cation and anion with CHARGES! 2
Not balanced!
2. Balance charges using the criss-cross method with subscripts, if necessary. Use parentheses if you need more than one of a polyatomic ion to balance subscripts.
Now balanced.
= Zn(OH)2

34. Writing Ionic Compound Formulas
Example: Magnesium carbonate (note the 2 word name)
1. Write the formulas for the cation and anion, including CHARGES!
Mg2+
CO32-
2. Check to see if charges are balanced.
They are balanced!
= MgCO3

35. Writing Ionic Compound Formulas
Example: Barium nitrate (note the 2 word name)
1. Write the cation and anion with CHARGES!
Ba2+
( )
NO3- 2
Not balanced!
2. Balance charges using the criss-cross method with subscripts, if necessary. Use parentheses if you need more than one of a polyatomic ion to balance subscripts.
Now balanced.
= Ba(NO3)2

36. Writing Ionic Compound Formulas
Example: Ammonium sulfate
( )
NH4+
SO42-
1. Write the cation and anion with CHARGES! 2
Not balanced!
2. Balance charges using the criss-cross method with subscripts, if necessary. Use parentheses if you need more than one of a polyatomic ion to balance subscripts.
Now balanced.
= (NH4)2SO4

37. Writing Ionic Compound Formulas
Example: Aluminum phosphate
1. Write the formulas for the cation and anion, including CHARGES!
Al3+
PO43-
They ARE balanced!
2. Check to see if charges are balanced.
= AlPO4

38. Naming Ionic Compounds
1. Cation first, then anion
2. Monatomic cation = name of the element
Ca2+ = calcium ion
3. Monatomic anion = root + -ide
Cl- = chloride
CaCl2 = calcium chloride

39. Naming Ionic Compounds
(Metals with multiple oxidation states)
If the metal can have more than one charge (Group B), use a Roman numeral in their name:
PbCl2  use the anion to find the charge on the cation (chloride is always 1-)
Pb2+ is the lead (II) cation
PbCl2 = lead (II) chloride

40. Things to look for:
If cations have ( ), the number in parenthesis is their charge.
If anions end in –ide, they are probably off the periodic table (Monoatomic)
If anion ends in -ate or –ite, then it is polyatomic

41. Practice by writing the formula or name as required…
Iron (II) Phosphate
Stannous Fluoride
Potassium Sulfide
Ammonium Chromate
MgSO4
FeCl3
𝐹𝑒 3 (𝑃𝑂 4 ) 2
SnF
𝐾 2 𝑆
( 𝑁𝐻 4 ) 𝐶𝑟𝑂 4 2
Magnesium Sulfate
Ferrous (III) Chloride

42. Nomenclature of Hydrates
A. Hydrate: Ionic compound with ______________ molecules stuck in the ___________ lattice. The water is included in the ____________ and formula.
Ex.
ZnSO4 7 H20: __________________________
CaCO3 3 H2O: __________________________
Cu2C2O4 2H2O: _________________________
Calcium chloride pentahydrate:______________
water
crystal
name
Zinc sulfate
heptahydrate
Calcium carbonate
trihydrate
Copper (I) oxalate
dihydrate
CaCl2
5H20

43. Section 9.3 Naming and Writing Formulas for Molecular Compounds

44. Molecular compounds are…
Made of only nonmetals
Smallest part is a molecule
Can’t use charges to figure out how many of each atom (there are no charges present / they share electrons)

45. Molecular compounds are easier!
Ionic compounds use charges to determine how many of each.
Figure out charges and criss-cross numbers.
Molecular compounds: the name tells you the number of atoms.
Uses prefixes to tell you the exact number of each element present!

46. Prefixes (Table 9.4, p.269) 9 = nona- 10 = deca- 1 = mono- 2 = di-
3 = tri-
4 = tetra-
5 = penta-
6 = hexa-
7 = hepta-
8 = octa-

47. Prefixes Prefix + name -ide
To write the name, include:
One exception is we don’t write mono if there is only one of the first element.
Normally, we do not have double vowels when writing names (oa oo)
Prefix + name -ide

48. Practice by naming these:
= dinitrogen monoxide (also called laughing gas)
N2O
NO2
Cl2O7
CBr4
CO2
BaCl2
= nitrogen dioxide
= dichlorine heptoxide
= carbon tetrabromide
= carbon dioxide
Ionic! So… Barium Chloride

49. Write formulas for these:
diphosphorus pentoxide
tetraiodine nonoxide
sulfur hexafluoride
nitrogen trioxide
carbon tetrahydride
phosphorus trifluoride
aluminum chloride
𝑃 2 𝑂 5
𝐼 4 𝑂 9
𝑆 𝐹 6
𝑁 𝑂 3
𝐶 𝐻 4
P 𝐹 3
𝐴𝑙 𝐶𝑙 3
(Ionic compound)

50. Section 9.4 Naming and Writing Formulas for Acids and Bases

51. Acids are…
Compounds that give off hydrogen ions (H+) when dissolved in water (the Arrhenius definition)
Formula starts with H.
Always be some Hydrogen next to an anion.
Anion determines the name.

52. Rules for Naming acids: Name it as a normal compound first
If the anion attached to hydrogen ends in -ide, put the prefix hydro- and change -ide to -ic acid
In other words, if it’s just Hydrogen and one other nonmetal
HCl =
H2S =
hydrochloric acid
hydrosulfuric acid

53. Naming Acids
If the anion has oxygen in it, then it ends in -ate or -ite
Change -ate to -ic acid (use no prefix)
Example: HNO Hydrogen + nitrate =
Change -ite to -ous acid (use no prefix)
Example: HNO Hydrogen + nitrite =
Nitric acid
Nitrous acid

54. Naming Acids ____-ide ____-ate ____-ite hydro-___-ic acid
Normal ending
____-ide
____-ate
____-ite
Acid name is…
hydro-___-ic acid
_____-ic acid
_____-ous acid

55. Practice by naming these:HF
H3P
H2SO4
H2SO3
HCN
H3PO4
Hydrofluoric Acid
Hydrophosphic Acid
Sulfuric Acid
Sulfurous Acid
Hydrocyanic Acid
Phosphoric Acid

56. Writing Acid Formulas – in reverse!
Hydrogen will be listed first
The name will tell you the anion
Be sure the charges cancel out.
Starts with hydro?
No hydro?
Anion is monatomic, ends in –ide
-ate anion comes from –ic ending
-ite anion comes from –ous ending

57. Write formulas for these:
hydroiodic acid
chloric acid
carbonic acid
phosphorous acid
hydrobromic acid 𝐻𝐼
𝐻𝐶𝑙𝑂 3
𝐻 2 𝐶 𝑂 3
𝐻 3 𝑃 𝑂 3
𝐻𝐵𝑟

58. Names and Formulas for Bases
Base - an ionic compound that produces hydroxide ions (OH1-) when dissolved in water (the Arrhenius definition)
Named the same way as other ionic compounds:
Name of cation (metal) followed by name of anion (which will be hydroxide).

59. Names and Formulas for Bases
NaOH =
Ca(OH)2 =
To write the formula:
Write symbol for metal cation
Followed by hydroxide ion (OH1-)
Use criss-cross method to balance the charges.
sodium hydroxide
calcium hydroxide

60. Practice by writing the formula for the following:
Magnesium hydroxide
Iron (III) hydroxide
Zinc hydroxide
𝑀𝑔(𝑂𝐻) 2
𝐹𝑒(𝑂𝐻) 3
𝑍𝑛(𝑂𝐻) 2

61. Section 9.5 The Laws Governing Formulas and Names

62. Some Laws:
Law of Definite Proportions- in a sample of a chemical compound, the masses of the elements are always in the same proportions.
In every molecule of H2O (water), the mass ratio of H:O is 1:8

63. Some Laws:
Law of Multiple Proportions- Whenever two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers.
H2O (water) and H2O2 (hydrogen peroxide)
2: :2
2g:16g g:32g

64.
Law of Definite Proportions - Law of Multiple Proportions
by Brightstorm

65. Summary of Naming and Formula Writing
For naming, follow the flowchart- Figure 9.20, page 277
For writing formulas, follow the flowchart from Figure 9.22, page 278

66. Helpful to remember...
1. In ionic compounds, the net charge is zero (criss-cross method)
2. Put -ide at the end of monatomic nonmetals
3. An -ite or -ate ending means there is a polyatomic ion that has oxygen
4. Prefixes generally mean molecular; they show the number of each atom

67. Helpful to remember...
5. A Roman numeral after the name of a cation is the charge of the cation

68. • Compounds Ionic Covalent Binary Ternary Acids Binary Ternary
(Metal / Non-metal)
Binary Ternary
Acids
Contain H+
Binary Ternary
w/ oxygen
Hydrates
Non-metal / Non-metal
Uses prefixes, -ide
I2O7 Diiodine heptoxide
2 elements
-ide
Roman numeral
(if needed)
ie. Calcium chloride
CaCl2
3 or more elements
Anion is named
Roman numerals
(if needed)
ie. Calcium carbonate
CaCO3
No oxygen
Hydro__ic acid
ie, Hydrochloric acid
HCl
-ate—ic
acid
H2CO3
Carbonic
-ite---ous
acid
H2SO3
Sulfurous
w/ H2O
Uses prefixes
ie. Calcium chloride
dihydrate
CaCl H2O •

69. Ion Bingo Set 2 (Choose 5 each for your blank sheet and mix them up)
Cations (Left side) Mg
Pb (II) Li Ca K Al
NH4
Anions (Top)
CO3
NO2
PO4 S Br
C2O4 Cl

70. Ion Bingo Set 2 (Choose 5 each for your blank sheet and mix them up)
Cations (Left side)
Fe (III) Zn Cs Sr Ni B
Cu (I)
Anions (Top)
SO3
ClO2
SO4 O F
C8H4O4 OH