1. Naming Compounds Writing Formulas
Chapter 9
Naming Compounds
Writing Formulas

2. Systematic Naming
There are too many compounds to remember the names of them all.
Compound is made of two or more elements.
Put together atoms.
Name should tell us how many and what type of atoms.

3. Periodic Table More than a list of elements.
Put in columns because of similar properties.
Each column is called a group.

4. Representative elements
The group A elements
The tall columns 5A 7A 2A 3A 4A 6A

5. Metals

6. Transition metals
The Group B elements

7. Non-metals
Dull
Brittle
Nonconductors- insulators

8. Metalloids or Semimetals
Properties of both
Semiconductors

9. Atoms and ions Atoms are electrically neutral.
Same number of protons and electrons.
Ions are atoms, or groups of atoms, with a charge.
Different numbers of protons and electrons.
Only electrons can move.
Gain or lose electrons.

10. F1- O2- Anion Has gained one electron Has gained two electrons
A negative ion.
Has gained electrons.
Non metals can gain electrons.
Charge is written as a superscript on the right.
F1-
Has gained one electron
O2-
Has gained two electrons

11. K1+ Ca2+ Cations Positive ions. Formed by losing electrons.
More protons than electrons.
Metals form cations.
K1+
Has lost one electron
Ca2+
Has lost two electrons

12. Two Types of Compounds Molecular compounds Made of molecules.
Made by joining nonmetal atoms together into molecules.

13. Two Types of Compounds Ionic Compounds Made of cations and anions.
Metals and nonmetals.
The electrons lost by the cation are gained by the anion.
The cation and anions surround each other.
Smallest piece is a FORMULA UNIT.

14. Two Types of Compounds Ionic Molecular Smallest piece Formula Unit
Molecule
Types of elements
Metal and Nonmetal
Nonmetals
Solid, liquid or gas
State
solid
Melting Point
High >300ºC
Low <300ºC

15. Chemical Formulas
Shows the kind and number of atoms in the smallest piece of a substance.
Molecular formula- number and kinds of atoms in a molecule.
CO2
C6H12O6

16. Formula Unit
The smallest whole number ratio of atoms in an ionic compound.
Ions surround each other so you can’t say which is hooked to which.

17. Charges on ions
For most of Group A elements, location on the Periodic Table can tell what kind of ion they form
Elements in the same group have similar properties.
Including the charge when they are ions.

18. Charge in groups 1A, 2A and 3A is the group number1+
in 5A, 6A and 7A is the group number - 8 2+ 3+ 3- 2- 1-

19. Can also use electron dots
If it has a few it loses them
If it has many, it gains enough for octet K + - F

20. Naming ions
Cation- if the charge is always the same (Group A) just write the name of the metal.
Most transition metals can have more than one type of charge.
Indicate the charge with Roman numerals in parenthesis.
Co2+ Cobalt(II) ion

21. Naming ions
A few, like silver, zinc and cadmium only form one kind of ion
Don’t get roman numerals
Ag+ silver ion
Zn2+ zinc ion
Cd2+ cadmium ion

22. Name these
Na1+
Sodium ion
Ca2+
Calcium ion
Al3+
Aluminum ion
Fe3+
Iron(III) ion
Fe2+
Iron(II) ion
Pb2+
Lead(II) ion
Li1+
Lithium ion

23. Write Formulas for these
K1+
Potassium ion
Mg2+
Magnesium ion
Cu2+
Copper(II) ion
Cr6+
Chromium(VI) ion
Ba2+
Barium ion
Hg2+
Mercury(II) ion

24. Naming Anions Anions are always the same
Change the element ending to – ide
F1- Fluoride ion

25. Name these
Cl1-
Chloride ion
N3-
Nitride ion
Br1-
Bromide ion
O2-
Oxide ion
Ga3+
Gallium ion

26. Write these
Sulfide ion
S2-
Iodide ion
I1-
Phosphide ion
P3-
Strontium ion
Sr2+

27. Polyatomic ions Groups of atoms that stay together and have a charge.
Covalently bonded
You must memorize these. (pg 257)

28. 1- ions Acetate C2H3O21- Nitrate NO31- Nitrite NO21- Hydroxide OH1-
Permanganate MnO41-
Cyanide CN1-

29. 1- ions Perchlorate ClO41- Chlorate ClO31- Chlorite ClO21-
Hypochlorite1-

30. 2- ions Sulfate SO42- Sulfite SO32- Carbonate CO32- Chromate CrO42-
Dichromate Cr2O72-
Silicate SiO32-

31. 3- ions
Phosphate PO43-
Phosphite PO33-
1+ ion
Ammonium NH41+

32. Adding Hydrogen to Polyatomics
Hydrogen ions are 1+
Attach to other polyatomic ions- changes charge by one
Sulfate SO42-
Hydrogen sulfate HSO41-
Phosphate PO43-
Hydrogen phosphate HPO42-
Dihydrogen phosphate H2PO41-

33. Naming Binary Ionic Compounds
Binary Compounds - 2 elements.
Ionic - a cation and an anion.
The name is just the names of the ions.
Cation first anion second
Easy with Group A elements.
NaCl = Na+ Cl- = sodium chloride
MgBr2 = Mg2+ Br- = magnesium bromide
Na2S

34. Naming Binary Ionic Compounds
The problem comes with the transition metals.
Cation name includes the charge.
The compound must be neutral.
same number of + and – charges.
Use the negative charge to find the charge on the positive ion.

35. Naming Binary Ionic Compounds
Write the name of CuO
Need the charge of Cu
O is 2-
copper must be 2+
Copper(II) oxide
Name CoCl3
Cl is 1- and there are three of them = 3-
Co must be 3+
Cobalt(III) chloride

36. Naming Binary Ionic Compounds
Write the name of Cu2S.
Since S is 2-, the Cu2 must be 2+, so each one is 1+.
copper(I) sulfide
Fe2O3
Each O is x 2- = 6-
2 Fe must = 6+, so each is 3+.
iron(III) oxide

37. Naming Binary Ionic Compounds
Write the names of the following
KCl
Na3N
CrN
Sc3P2
PbO
PbO2
Na2Se

38. Ternary Ionic Compounds
Will have polyatomic ions
At least three elements (3 capital letters)
Still just name the ions
NaNO3
CaSO4
CuSO3

39. Ternary Ionic Compounds
(NH4)2O
Fe(OH)3
LiCN
(NH4)2CO3
NiPO4

40. Writing Formulas The charges have to add up to zero.
Get charges on pieces.
Cations from name or periodic table.
Anions from periodic table or polyatomic.
Balance the charges by adding subscripts.
Put polyatomics in parenthesis if there is more than one of them

41. Writing Formulas Write the formula for calcium chloride.
Calcium is Ca2+
Chloride is Cl1-
Ca2+ Cl1- would have a 1+ charge.
Need another Cl1-
Ca2+ Cl21-

42. 3 2 Ba2+ N3- Ba3 N2 Crisscross Reduce ratio if possible
Switch the numerical value of the charges
Ba2+
N3- 2 3
Ba3 N2
Reduce ratio if possible

43. Write the formulas for these
Lithium sulfide
tin (II) oxide
tin (IV) oxide
Copper (II) sulfate
Iron (III) phosphide
gallium nitrate
Iron (III) sulfide
ammonium sulfide

44. Write the formulas for these
Ammonium chloride
barium nitrate

45. Things to look for
If cations have (), the number is their charge. Not how many.
If anions end in -ide they are probably off the periodic table (Monoatomic)
If anion ends in -ate or -ite it is polyatomic
The positive piece always gets written first
Hydrogen- it depends on where it’s at
If it is second, it’s a nonmetal -hydride

46. Writing names and Formulas
Molecular Compounds
Writing names and Formulas

47. Molecular compounds made of just nonmetals
smallest piece is a molecule
can’t be held together because of opposite charges.
can’t use charges to figure out how many of each atom

48. Easier Ionic compounds use charges to determine how many of each.
Have to figure out charges.
Have to figure out numbers.
Molecular compounds name tells you the number of atoms.
Uses prefixes to tell you the number

49. Prefixes 6 hexa- 7 hepta- 8 octa- 9 nona- 10 deca- 1 mono- 2 di-
3 tri-
4 tetra-
5 penta-
6 hexa-
7 hepta-
8 octa-
9 nona-
10 deca-

50. Naming Prefix name Prefix name -ide To write the name write two words
Exception - we don’t write mono- if there is only one of the first element.
No ao oo double vowels when writing name, io, oi, and ai are okay.

51. Name These
N2O
NO2
Cl2O7
CBr4
CO2
BaCl2

52. Write formulas for these
diphosphorus pentoxide
tetraiodine nonoxide
sulfur hexaflouride
nitrogen trioxide
Carbon tetrahydride
phosphorus trifluoride
aluminum chloride

53. Writing names and Formulas
Acids
Writing names and Formulas

54. Acids Compounds that give off hydrogen ions when dissolved in water.
Must have H in them.
will always be some H next to an anion.
The anion determines the name.

55. Naming acids
If the anion attached to hydrogen is ends in -ide, put the prefix hydro- and change -ide to -ic acid
HCl - hydrogen ion and chloride ion
hydrochloric acid
H2S hydrogen ion and sulfide ion
hydrosulfuric acid

56. Naming Acids If the anion has oxygen in it it ends in -ate or -ite
change the suffix -ate to -ic acid
HNO3 Hydrogen and nitrate ions
Nitric acid
change the suffix -ite to -ous acid
HNO2 Hydrogen and nitrite ions
Nitrous acid

57. Name these HF
H3P
H2SO4
H2SO3
HCN
H2CrO4

58. Writing Formulas Hydrogen will always be first
name will tell you the anion
make the charges cancel out.
Starts with hydro- no oxygen, -ide
no hydro, -ate comes from -ic, -ite comes from -ous

59. Write formulas for these
hydroiodic acid
acetic acid
carbonic acid
phosphorous acid
hydrobromic acid

60. Name these acids a) H2C2O4 b) HF c) HClO2 d) H2CO3
Write formulas for these compounds a) nitrous acid b) hydroselenic acid c) phosphoric acid d) acetic acid
43. Name these compounds a) AlF3 b) SnO2 c) Fe(C2H3O2)3 d) KHSO4 e) CaH2 f) HClO3 g) Hg2Br2 h) H2CrO4
44. Write formulas for these a) Phosphorus pentabromide b) Carbon chloride c) potassium permanganate

61. 43. Name these compounds a) AlF3. b) SnO2. c) Fe(C2H3O2)3 d) KHSO4
43. Name these compounds a) AlF3 b) SnO2 c) Fe(C2H3O2)3 d) KHSO4 e) CaH2 f) HClO3 g) Hg2Br2 h) H2CrO4
44. Write formulas for these a) Phosphorus pentabromide b) Carbon chloride c) potassium permanganate d) Calcium hydrogen carbonate e) dichlorine heptoxide f) trisilicon tetrahydride g) sodium dihydrogen phosphate

62. Summary Without O -ide With O -ite and -ate Periodic table
Grouped by properties
Metals- make cations
2 types those with () and those without
Nonmetals make anions
Three types
Without O -ide
With O -ite and -ate
Only electrons can move to make ions

63. Summary Make all the decisions. First determine type of compound
Then figure out name or formula
Acid = H to start
Metal = Ionic
No H, No metal = molecular
Only molecular get prefixes
Roman numeral is NOT how many
Hydro means no O