Chemical Bonding

1
Chemical Bonding
2
Definition

• A chemical bond is an attraction between the
  nuclei and valence electrons of atoms
• The chemical bond holds atoms together in
  compounds
• Bonding decreases the energy of the atoms (this
  is a state that is favored)

3
Two Main Types of Bonding

• Covalent bonding
• Atoms share electrons
• Ionic bonding
• Atoms gain or lose electrons, creating ions
• Anions attract cations, holding the ions together

4
Bonding

• The nature of bonding is usually somewhere in
  between pure covalent and pure ionic
• See Figure 6-2 page 162
• Covalent bonds
• Nonpolar electronegativity difference between
  atoms is less than 0.3
• Polar electronegativity difference between atoms
  is between 0.3 and 1.7
• Ionic bonds
• Electronegativity difference is greater than 1.7
  between atoms

5
Sample problem 6-1

• Use electronegativity (p 151) differences and
  Figure 6-2 to classify bonding between sulfur
  and
• Hydrogen
• H 2.1 S 2.5 Difference 0.4
• Bonding is polar covalent
• Cesium
• Cs 0.7 S 2.5 Difference 1.8
• Bonding is ionic
• Chlorine
• Cl 3.0 S 2.5 Difference 0.5
• Bonding is polar covalent