Zumdahl • DeCoste chemistry world of Chapter 12

Zumdahl • Zumdahl • DeCoste

• CHEMISTRY

• World of

Chapter 12

• Chemical Bonding

Chapter 12 Overview

• Ionic & covalent bonds & their formation
• Polar covalent bonds
• Bond relationships to electronegativity
• Bond polarity & its relationship to molecular polarity
• Ionic structures
• Ionic size
• Lewis structures
• Molecular structures & bond angles
• VSEPR model

Why are graphite and diamonds so different even though they are both carbon?

• The carbon atoms are bound differently
• Structure & shape very important
• Different properties
• Reactions
• Smell
• Taste

Types of Chemical Bonds

• Bond: force that holds groups of 2 or more atoms together and makes them function as a unit
• Bond Energy: the energy required to break a bond
• Ionic Bonding: attraction between oppositely charged ions
• Ionic Compound: result of metal reacting with a nonmetal
• Covalent Bonding: bonding where atoms share electrons
• Polar Covalent Bond: covalent bond where electrons are not shared equally because on atom attracts them more strongly than the other

Figure 12.1: The formation of a bond between two atoms.

• Covalent Bond

Figure 12.2: Probability representations of the electron sharing in HF.

• Polar Covalent Bond

Electronegativity

• The relative ability of an atom in a molecule to attract shared electrons to itself
• Chemists determine by measuring the polarities of bonds between different atoms
• Higher value = higher attraction of electrons
• Difference between electronegativity values determines polarity of molecule
• Larger difference = more polar
• Smaller difference = more equally shared
• If difference is greater than 2 – bond is ionic (electrons are transferred)