Ionic and Covalent Bonding

Question 1

What are the 3 physical properties of a covalent compound with simple molecular structure?

Answer 1

1. Low Melting and Boiling Points
2. Unable to conduct electricity in any state
3. Insoluble in water, soluble in organic solvents

Question 2

What are the 3 physical properties of an ionic compound?

Answer 2

1. High Melting and Boiling Point
2. Ability to conduct electricity in Molten and Aqueous States
3. Soluble in water, Insoluble in organic solvents

Question 3

Why do most Ionic compounds have high melting and boiling points? Explain FULLY

Answer 3

1. Ionic compounds have a giant ionic crystal lattice structure
2. where strong electrostatic forces of attraction (ionic bonds) act between oppositely charged ions.
3. Thus, a large amount of energy is required to overcome these forces of attraction,
4. leading to high mp and bp

Question 4

Why do most covalent compounds have low melting and boiling points? Explain FULLY

Answer 4

1. Most covalent compounds have a simple molecular structure
2. with weak (van der waals) intermolecular forces of attraction between the molecules.
3. Thus a relatively smaller amount of energy is required to overcome those forces of attraction,
4. leading to low mp and bp.

Question 5

(pure) Why does Diamond have a high melting point?

Answer 5

1. Diamond has a Giant molecular structure
2. consisting of a vast network of carbon atoms,
3. each being bonded to four other carbon atoms in a tetrahedral arrangement
4. by strong covalent bonds.
5. Thus a large amount of energy is required to break the covalent bonds,
6. leading to a high melting point.

Question 6

(pure) Why does Graphite have a high melting point?

Answer 6

1. Graphite has a Giant molecular structure
2. consisting of a vast network of carbon atoms,
3. each being bonded to three other carbon atoms, by strong covalent bonds,
4. forming sheets of carbon atoms in a hexagonal arrangement.
5. Thus a large amount of energy is required to break the covalent bonds,
6. leading to a high melting point.

Question 7

(pure) Why is Graphite able to conduct electricity while Diamond is not?

Answer 7

1. In graphite, each C atom is only bonded to 3 other atoms,
2. leaving one free electron that is delocalized.
3. In Diamond, the electrons in each C atom are fully involved in bonding
4. as each C atom is bonded to four other C atoms in a tetrahedral arrangement
5. Therefore there are no free, delocalized electrons available to conduct electricity.