1. Chemical Bonds, Names and Formulas
Unit # 6

2. Big Ideas
OBJECTIVES:
Distinguish between ionic and molecular compounds.
Distinguish between ionic, covalent and metallic bonds
Define cation and anion, and relate them to metal and nonmetal.
Name molecules and compounds

3. What is a bond?
The valence electron of one atom is attracted to the nucleus of another atom
Reasons Why?
Mutual attraction
To achieve a full valence shell
To have lower Kinetic Energy

4. Covalent Bonds When a pair of electrons are “shared” between two atoms
This will occur between atoms that have similar electronegativity values
Non-metal bonded to non-metal

5. Covalent Bonds
Single bond – one pair of electrons are shared (2 electrons)
Double bond – two pairs of electrons are shared (4 electrons)
Triple bond – three pairs of electrons are shared (6 electrons)

6. Ionic Bonds An unequal sharing of a pair of electrons between atoms
Between a metal and a non-metal
We usually say “ the metal will give up the electron and the non-metal will take the electron
Atoms that have a electronegativity difference higher than 1.7

7. Metallic Bonds Bonds between 2 metals
Both metals will give up electrons and then share the “sea of electrons”

8. Determine the bond type
H2O
HCl
NaCl
KCr
KBr

9. Determine the bond type
H2O covalent
HCl covalent
NaCl ionic
KCr metallic
KBr Ionic

10. Let’s Review some old concepts to tie this together

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

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

13. K1+ Ca2+ Cations Positive ions. Formed by losing electrons.
More protons than electrons.
Metals can lose electrons
K1+
Has lost one electron (no name change for positive ions)
Ca2+
Has lost two electrons

14. Now let’s bond the old material to the new material
Back to New Material
Now let’s bond the old material to the new material

15. Two types of Compounds
Ionic and molecular

16. Ionic Compounds
Ionic compounds- from joining metal and nonmetal - they are electrically neutral
Metal and polyatomic ion
Ionic Bonds

17. Ionic Compounds
This formula represents not a molecule, but a 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.

18. Molecules and Molecular Compounds
Made of molecules.
Made by joining nonmetal atoms together into molecules.
Covalent bonds

19. Molecules and Molecular Compounds
Molecule- smallest electrically neutral unit, still has properties of the substance
Made from only nonmetals
Can be from one element- O2
Can make a compound- CO2

20. Two Types of Compounds Ionic Molecular Smallest piece Formula Unit
Molecule
Types of elements
Metal and Nonmetal
Nonmetals
Solid, liquid or gas
State
solid
Bond Type
Ionic
Covalent

21. 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

22. Chemical Formulas More than one atom? –use a subscript (H2O)
There are 7 diatomic elements
Hydrogen (H2), Nitrogen (N2), Oxygen (O2), Fluorine (F2), Chlorine (Cl2), Bromine (Br2), and Iodine (I2)
Remember: “Br I N Cl H O F”

23. Charges on ions Elements in the same group have similar properties.
Including the charge when they are ions
Remember Group 1 forms +1 ions

24. 1+ 2+ 3+ 3- 2- 1-

25. What about the others?
Many transition metals have more than one common ionic charge
We use roman numerals in naming

26. More Big ideas OBJECTIVES: Name ions based on their oxidation state
Define a polyatomic ion, and give the names and formulas of the most common polyatomic ions.

27. Naming ions Two methods if more than one charge is possible:
1. Stock system – uses roman numerals in parenthesis to indicate the numerical value
2. Classical method – uses root word with suffixes (-ous, -ic)
Does not give true value

28. Naming ions We will use the Stock system.
Cation- if the charge is always the same (Group A) just write the name of the metal.
Transition metals can have more than one type of charge.
Indicate the charge with roman numerals in parenthesis

29. Name these
Na1+
Ca2+
Al3+
Fe3+
Fe2+
Pb2+
Li1+

30. Write Formulas for these
Potassium ion
Magnesium ion
Copper (II) ion
Chromium (VI) ion
Barium ion
Mercury (II) ion

31. Naming Anions Anions are always the same charge
Change the element ending to – ide
F1- Fluorine

32. Naming Anions Anions are always the same charge
Change the element ending to – ide
F1- Fluorin

33. Naming Anions Anions are always the same charge
Change the element ending to – ide
F1- Fluori

34. Naming Anions Anions are always the same charge
Change the element ending to – ide
F1- Fluor

35. Naming Anions Anions are always the same charge
Change the element ending to – ide
F1- Fluori

36. Naming Anions Anions are always the same charge
Change the element ending to – ide
F1- Fluorid

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

38. Name these
Cl1-
N3-
Br1-
O2-
Ga3+

39. Write these
Sulfide ion
iodide ion
phosphide ion
Strontium ion

40. Exceptions: Some of the transition metals have only one ionic charge:
Do not use roman numerals for these:
Silver is always 1+ (Ag1+)
Cadmium and Zinc are always 2+ (Cd2+ and Zn2+)

41. Polyatomic ions Groups of atoms that stay together and have a charge.
Acetate C2H3O21-
Nitrate NO31-
Nitrite NO21-
Hydroxide OH1- and Cyanide CN1-
Permanganate MnO41-

42. Polyatomic ions Sulfate SO42- Sulfite SO32- Carbonate CO32-
Chromate CrO42-
Dichromate Cr2O72-
Phosphate PO43-
Phosphite PO33-
Ammonium NH41+

43. Big Idea
OBJECTIVES:
Apply the rules for naming and writing formulas for binary ionic and ternary ionic compounds.

44. Naming Binary Ionic Compounds
Binary Compounds - 2 elements.
Ionic - a cation and an anion.
To write the names, just name the two ions.
Easy with Representative elements (which are Group A elements)
NaCl = Na1+ Cl1- = sodium chloride
MgBr2 = Mg2+ Br1- = magnesium bromide

45. Naming Binary Ionic Compounds
The problem comes with the transition metals.
Need to figure out their charges.
The compound must be neutral.
same number of + and – charges.
Use the anion to determine the charge on the positive ion.

46. 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

47. 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

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

49. Ternary Ionic Compounds
These will have polyatomic ions
At least three elements
name the ions
NaNO3
CaSO4
CuSO3
(NH4)2O

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

51. Writing Formulas The charges have to add up to zero.
Get charges on pieces.
Cations from name on table.
Anions from table or polyatomic.
Balance the charges by adding subscripts.
Put polyatomics in parenthesis.

52. 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- (use criss-cross method)

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

54. Write the formulas for these
Ammonium chloride
ammonium sulfide
barium nitrate

55. 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 it is polyatomic

56. Section 6.5 Molecular Compounds and Acids
OBJECTIVES:
Apply the rules for naming and writing formulas for binary molecular compounds.

57. Section 6.5 Molecular Compounds and Acids
OBJECTIVES:
Name and write formulas for common acids.

58. 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

59. Molecular are 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

60. Prefixes (Table 6.5, p.159) 1 = mono- 2 = di- 3 = tri- 4 = tetra-
5 = penta-
6 = hexa-
7 = hepta-
8 = octa-

61. Prefixes
9 = nona-
10 = deca-
To write the name, write two words:

62. Prefixes Prefix name Prefix name -ide 9 = nona- 10 = deca-
To write the name, write two words:
Prefix
name
Prefix
name
-ide

63. Prefixes Prefix name Prefix name -ide 9 = nona- 10 = deca-
To write the name, write two words:
One exception is we don’t write mono- if there is only one of the first element.
Prefix
name
Prefix
name
-ide

64. Prefixes Prefix name Prefix name -ide 9 = nona- 10 = deca-
To write the name, write two words:
One exception is we don’t write mono- if there is only one of the first element.
No double vowels when writing names (oa oo)
Prefix
name
Prefix
name
-ide

65. Name These
N2O
NO2
Cl2O7
CBr4
CO2
BaCl2

66. Write formulas for these
diphosphorus pentoxide
tetraiodine nonoxide
sulfur hexafluoride
nitrogen trioxide
carbon tetrahydride
phosphorus trifluoride
aluminum chloride

67. Writing names and Formulas
Acids
Writing names and Formulas

68. 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.

69. Naming acids
If the anion attached to hydrogen 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

70. Naming Acids
If the anion has oxygen in it, then it ends in -ate of -ite
change the suffix -ate to -ic acid (use no prefix)
HNO3 Hydrogen and nitrate ions
Nitric acid
change the suffix -ite to -ous acid
HNO2 Hydrogen and nitrite ions
Nitrous acid

71. Name these HF
H3P
H2SO4
H2SO3
HCN
H2CrO4

72. Writing Acid 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

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

74. Section 6.6 Summary of Naming and Formula Writing
OBJECTIVES:
Use the flowchart in Figure 6.21 to write the name of a compound when given its chemical formula.

75. Section 6.6 Summary of Naming and Formula Writing
OBJECTIVES:
Use the flowchart in Figure 6.23 to write a chemical formula when given the name of a compound.

76. Helpful to remember...
1. In an ionic compound, the net ionic charge is zero (criss-cross method)
2. An -ide ending generally indicates a binary compound
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

77. Helpful to remember...
5. A Roman numeral after the name of a cation shows the ionic charge of the cation
Use the handout sheets provided by your teacher!

78. Summary of Naming and Formula Writing
For naming, follow the flowchart- Fig. 6.21, page 161
For writing formulas, follow the flowchart from Fig. 6.23, p. 162