Ch' 6 Chemical Bonds

1
Ch. 6 - Chemical Bonds

• I. Why Atoms Combine
• Chemical Bond
• Stability
• Ions
• Chemical Formula

2
A. Chemical Bond

• Strong attractive force that holds atoms or ions
  together as a unit.
• Formed by
• transferring e- (losing or gaining)
• sharing e-

3
B. Stability

• Octet Rule
• most atoms form bonds in order to have 8 valence
  e-
• full outer energy level
• like the Noble Gases!

• Stability is the driving force behind bond
  formation!

4
C. Ions

• Ion Formation
• Atoms gain or lose electrons to form ions and
  become more stable.
• Ionization Energy is the energy needed to take an
  electron away from an atom
• Football analogy

5
C. Ions

• Cation positive charge (electrons lost)

• Anion negative charge (electrons gained)

6
C. Ions

• A neutral Mg atom has
• 12 p
• 12 e-
• 2 valence e-

Mg2

• Loses 2 electrons to become
• 12 p
• 10 e-

2 unbalanced p
7
C. Ions

• A neutral F atom has
• 9 p
• 9 e-
• 7 valence e-

F1-

• Gains 1 electrons to become
• 9 p
• 10 e-

1 extra e-
8
C. Ions

• Short-cut

1
0
2
3
4
3-
2-
1-
9
C. Ions

• Transferring e-

10
D. Chemical Formula

• Shows
• 1) elements in a compound
• 2) ratio of their atoms

H2O