Covalent Bonding

Question 1

What is a covalent bond? Give an example.

Answer 1

A bond between a non-metal and non-metal formed by sharing a pair of electrons between the two atoms.

Example, Hydrogen Chloride (HCl)

Question 2

Describe the electrostatic attraction in a covalent bond.

Answer 2

There is a strong electrostatic attraction between the shared pair of electrons and the nuclei of the atoms involved.

Question 3

Describe covalent bonds’ melting and boiling points

Answer 3

The intermolecular forces between the molecules are weak attractive forces.
The larger the molecule gets (increase in Mr), the more intermolecular forces that hold its molecules together.
Therefore more energy is required to overcome the intermolecular forces of large molecules
Causing the BPT and MPT to be high

Question 4

Describe covalent bonds’ electrical conductivity

Answer 4

Covalent Compounds do not conduct electricity as they do not have delocalised electrons that are free to move and carry charged

Question 5

Describe the properties of Diamond

Answer 5

- Hard 
Each Carbon atom is joined to 4 other Carbon atoms, forming a giant covalent structure and strong covalent bonds 
- High MP and BP 
It is a giant covalent structure 
That has many strong covalent bonds 
That needs to be broken down 
Therefore lots of heat energy is needed to overcome forces and break the bonds 
- Does Not Conduct Electricity 
Electrons are used in covalent bonds
So there are no delocalised electrons 
That are free to move and carry charge 
- Uses 
cutting tools, jewellery

Question 6

Describe the properties of Graphite

Answer 6

• Soft and Slippery
  Graphite is made up of two-dimensional layers of carbon atoms
  Which are held by weak forces of attraction
  These layers of graphite can slide over each other
  Making it soft and slippery
• High MP and BP
  In each layer, each C atom forms strong covalent bonds with three other C atoms in a giant covalent structure Therefore lots of heat energy is needed to overcome the forces and break the bonds
• Conducts Electricity
  Only three outer electrons of each C is in a covalent bond
  Therefore the fourth electron is delocalised between the layers
  And is free to move and carry charge
• Uses
  Lubricant

Question 7

Describe the properties of Fullerene

Answer 7

• Soft
  Each C atom is joined to only three other C atoms and
  There are weak intermolecular forces of attraction between the molecules
  Therefore the intermolecular bonds can be broken down easily making it soft
• Low MP and BP
  Each carbon atom is joined to only three other C atoms.
  This means that there are weak intermolecular forces of attraction between molecules
  Therefore only small amounts of heat energy is required to overcome these forces and break the bonds
• Does not conducts electricity
  Although they contain delocalised electrons
  The distance between the bulkyballs is too far for the delocalised electrons to move across
• Uses
  lubricant