Topic 3.

Question 1

What is a covalent bond?

Answer 1

Covalent bonding as electrostatic attraction between the nuclei of two atoms and a shared pair of
electrons.

Question 2

What is an ionic bond?

Answer 2

Ionic bonds are the electrostatic forces of attraction between opposite charged ions (positively charged cations and negatively charged anions).

Question 3

What is a metallic bond?

Answer 3

Metallic bonding as the electrostatic attraction between positive metal ions and delocalised electrons.

Question 4

What is electronegativity?

Answer 4

Electronegativity is the ability of an atom to attract a bonding pair of electrons in a covalent bond.

Question 5

What are the 7 shapes of molecules?

Answer 5

• Linear.
• Trigonal planar.
• Non-linear.
• Pyramidal.
• Tetrahedral.
• Trigonal bipyramidal.
• Octahedral.

Question 6

Explain a linear molecule shape in terms of:
- Number of bonding pairs.
- Number of lone pairs.
- Degrees.
- Example.

Answer 6

• Number of bonding pairs:
  2 bonding pairs.
• Number of lone pairs:
  No lone pairs.
• Degrees:
  180°.
• Example:
  Carbon dioxide CO₂.

Question 7

Explain a trigonal planar molecule shape in terms of:
- Number of bonding pairs.
- Number of lone pairs.
- Degrees.
- Examples.

Answer 7

• Number of bonding pairs:
  3 bonding pairs.
• Number of lone pairs:
  No lone pairs.
• Degrees:
  120°.
• Example:
  Boron trifluoride BF₃.

Question 8

Explain a tetrahedral molecule shape in terms of:
- Number of bonding pairs.
- Number of lone pairs.
- Degrees.
- Example.

Answer 8

• Number of bonding pairs:
  4 bonding pairs.
• Number of lone pairs:
  No lone pairs.
• Degrees:
  109.5°.
• Example:
  Methane CH₄.

Question 9

Explain a pyramidal molecule shape in terms of:
- Number of bonding pairs.
- Number of lone pairs.
- Degrees.
- Examples.

Answer 9

• Number of bonding pairs:
  3 bonding pairs.
• Number of lone pairs:
  1 lone pair.
• Degrees:
  107°.
• Examples:
  Ammonia NH₃.

Question 10

Explain a non-linear molecule shape in terms of:
- Number of bonding pairs.
- Number of lone pairs.
- Degrees.
- Examples.

Answer 10

• Number of bonding pairs:
  2 bonding pairs.
• Number of lone pairs:
  1 or 2 lone pairs.
• Degrees:
  104.5°.
• Example:
  Water H₂0.
  Sulfur dioxide SO₂.

Question 11

Explain a octahedral molecule shape in terms of:
- Number of bonding pairs.
- Number of lone pairs.
- Degrees.
- Examples.

Answer 11

• Number of bonding pairs:
  6 bonding pairs.
• Number of lone pairs:
  No lone pairs.
• Degrees:
  90°.
• Example:
  Sulfur hexafluoride SF₆.

Question 12

Explain a trigonal bipyramidal molecule shape in terms of:
- Number of bonding pairs.
- Number of lone pairs.
- Degrees.
- Examples.

Answer 12

• Number of bonding pairs:
  5 bonding pairs.
• Number of lone pairs:
  No lone pairs.
• Degrees:
  90° and 120°.
• Example:
  Phosphorus pentafluoride PF₅.