1. I. Why Atoms Combine Chemical Formulas Chemical Bonds Stability

2. H2O A. Chemical Formula 1 oxygen atom 2 hydrogen atoms Shows:
1) elements in the compound
2) ratio of their atoms
H2O
1 oxygen atom
2 hydrogen atoms

3. B. Chemical Bond
Strong attractive force between atoms or ions in a molecule or compound.
Formed by:
transferring e- (losing or gaining)
sharing e-

4. C. Stability Stability is the driving force behind bond formation
Elements can gain, lose or share electrons to become stable
Octet Rule
most atoms form bonds in order to have 8 valence e-
want a full outer energy level
like the Noble Gases

5. C. Stability
Transferring e-
Sharing e-

6. II. Kinds of Chemical Bonds Ionic Bond Covalent Bond Comparison Chart

7. A. Ionic Bond Attraction between 2 oppositely charged ions.
Ions are charged atoms.
A cation is a positively charged ion (Forms when an atom loses an e-)
Formed by metals.
An anion is a negatively charged ion (Forms when an atom gains an e-)
Formed by nonmetals.
Ions are formed by transferring e- from a metal to a nonmetal.

8. A. Ionic Bond
ions form a 3-D crystal lattice
NaCl

9. B. Covalent Bond Attraction between neutral atoms.
formed by sharing e- between two nonmetals

10. B. Covalent Bond
covalent bonds result in molecules
NH3
H2O
Cl2

11. B. Covalent Bond Nonpolar Covalent Bond e- are shared equally
usually identical atoms

12. + - B. Covalent Bond Polar Covalent Bond
e- are shared unequally between 2 different atoms
results in partial opposite charges + -

13. C. Comparison Chart IONIC COVALENT transferred from metal to nonmetal
shared between nonmetals
Electrons
Melting
Point
high
low
Polar = yes
Nonpolar = no
Soluble in
Water
yes
Conduct Electricity
yes (solution or liquid) no
crystal lattice of ions, crystalline solids
molecules, odorous liquids & gases
Other
Properties
Types of Elements
Metal and Nonmetal
Nonmetal ONLY

14. Both types of bonds
Some compounds have a mixture of ionic and covalent bonds.
These generally contain POLYATOMIC IONS.
Polyatomic ions are groups of non-metal elements bonded covalently together that have an overall charge
Generally polyatomic ions will form an ionic bond with metal.
They are easy to recognize because they have three or more elements in the compound.
Examples: Na3PO4, Al2(SO3)3

15. Practice What type of compound is show or described below? NaCl CO2
Fe2O3
Ga(C2H3O2)3
Metal and nonmetal
2 non metal
3 or more elements
Doesn’t dissolve in water
Ionic
Covalent
Both (polyatomic)
Both (polyatomic)nt

16. III. Naming Molecular Compounds Molecular Names Molecular Formulas
Chemical Bonds
III. Naming Molecular Compounds
Molecular Names
Molecular Formulas

17. A. Molecular (Covalent) Names
Write the names of the 1st element.
Write the first part of the name for the 2nd element then change the final ending to -ide.
Add prefixes to indicate subscripts.
Only use mono- prefix with second element. [NEVER have mono- on 1st element in compound]

18. PREFIX mono- di- tri- tetra- penta- hexa- hepta- octa- nona- deca-
SUBSCRIPT
Covalent Naming Prefixes

19. A. Molecular Names CCl4 N2O carbon tetrachloride SF6
dinitrogen monoxide
sulfur hexafluoride

20. B. Molecular Formulas Write the more metallic element first.
Add subscripts according to prefixes.

21. B. Molecular Formulas phosphorus trichloride dinitrogen pentoxide PCl3
dihydrogen monoxide
PCl3
N2O5
H2O

22. In nature, these elements are never alone!
B. Molecular Formulas
The Seven Diatomic Elements
Br2 I2 N2 Cl2 H2 O2 F2
In nature, these elements are never alone!

23. IV. Naming Ionic Compounds Oxidation Number Ionic Names Ionic Formulas
Chemical Bonds
IV. Naming Ionic Compounds
Oxidation Number
Ionic Names
Ionic Formulas

24. A. Oxidation Number The charge on an ion.
Indicates the # of e- gained/lost to become stable. 1+ 2+ 3+ 4+ 3- 2- 1-

25. Oxidation Chart Group # 1 2 13 14 15 16 17 18 Valence e- 3 4 5 6 7 8+1 +2 +3 -3 -2 -1
+/-4

26. B. Ionic Names Write the names of the cation first. (the metal)
Change the anion’s (non-metal) ending to -ide.

27. B. Ionic Names NaBr Na3P2 sodium bromide SnCl4 sodium phosphide
Tin chloride

28. Writing Ionic Formulas
Crisscross method.
IF the charges don’t balance the number of the charge becomes the subscript for the opposite element or polyatomic ions.
Example
The charges BALANCE thus disappear.
Mg N-3
= Mg3N2

29. Writing Formulas Example 2: Aluminum Sulfide Example 3: sodium oxide
Al+3 S-2
Al2S3
Example 3: sodium oxide
Na2O

30. C. Ionic Names to Formulas
Look at the given name
Write each ion. Put the cation first.
Overall charge must equal zero.
If charges cancel, just write the symbols.
If not, crisscross the charges to find subscripts.

31. C. Ionic Formulas potassium chloride magnesium fluoride K+ Cl-  KCl
aluminum oxide
K+ Cl-  KCl
Mg2+ F-1  MgF2
Al3+ O-2  Al2O3

32. Mixed Names to Formulas
Covalent Names
Have prefixes in the name
Use the prefix to write the chemical formula
Write what the name tells you to write.
Dinitrogen hexaphosphide
N2P6
Ionic Names
NO PREFIXES
Must write ions and balance charges.
Remember NO charges in chemical formulas.
Will see polyatomic items. (end in ite or ate)
Calcium phosphide
Ca+2 P-3
Ca3P2

33. Mixed Formula to Names Covalent Formulas Ionic Formulas
Have ONLY nonmetals
Write the name of each element
Change the end of the 2nd element to ide
ADD PREFIXES to show the number of atoms CO
Carbon monoxide
Ionic Formulas
Have metal and nonmetal
Write the name of each element
Change the end of the 2nd element to ide
IF 3 or more elements in compound use polyatomic list to fide its special name.
K3N
Potassium nitride

34. Properties of Ionic compounds
From by transferring electrons
Metals lose electrons
form positively charged cations
Nonmetals gain electrons
Form negatively charged anions
Are crystalline solids (form crystals)
with very high melting points
Are soluble in water (can dissolve)
When dissolved in water will conduct electricity

35. Properties of covalent compounds
Form by sharing electrons
Between two neutral nonmetal atoms
Most are liquids or gases
Also called molecules
Many covalent compounds have no odor
Have very low melting points
Most are not soluble in water
Do not conduct electricity

36. C. Comparison Chart IONIC COVALENT transferred from metal to nonmetal
shared between nonmetals
Electrons
Melting
Point
high
low
Soluble in
Water
yes
usually not
Conduct Electricity
yes (solution or liquid) no
crystal lattice of ions, crystalline solids
molecules, odorous liquids & gases
Other
Properties
Types of Elements
Metal and Nonmetal
Nonmetal ONLY