Bonding And Structure

Question 1

Why do ionic compounds have high melting and boiling points and are strong crystalline solids ?

Answer 1

• arranged in a regular giant ionic lattice which continues in 3 dimensions.
• held together by strong ESFOA
• take a lot of energy to overcome

Question 2

Why do ionic compounds only conduct electricity when molten/ in aqueous solution?

Answer 2

Because when solid, the ions are arranged in a giant ionic lattice and not free to move, when molten the ions are free to move and carry the charge.

Question 3

Definition of a covalent bond

Answer 3

The ESFOA between the positive nuclei and negative electrons.

Question 4

Why are simple molecular substances gases or liquids with low melting and boiling points?

Answer 4

• the intermolecular forces are weak and can be easily overcome

Question 5

Why do substances with simple molecular substances not conduct electricity?

Answer 5

They do not have charged particles able to move

Question 6

Why do the melting and boiling points f substances with simple molecular structures increase with relative molecular mass?

Answer 6

• more particles

- more bonds to overcome

Question 7

List 3 properties of diamond and explain them.

Answer 7

• hard and strong (giant molecular substance with many bonds, every carbon atom forms 4 strong covalent bonds with other carbon atoms)
• high melting and boiling point (the strong covalent bonds take a lot of energy to overcome)
• does not conduct electricity (all the outer shell electrons are shared in covalent bonds, there are no free electrons or other charged particles able to move)

Question 8

List 3 properties or graphite and explain them

Answer 8

• soft and slippery substance (layered structure, the London forces between layers are weak and easily overcome)
• high melting and boiling points (strong covalent bonds within the layers, take a lot of energy to overcome)
• conducts electricity (fourth electron from each atom of carbon is delocalised because each graphite atom forms 3 bonds is therefore able to move)

Question 9

List 2 properties of C60 fullerene and explain them

Answer 9

• low melting and boiling point (weak intermolecular forces take little energy to overcome)
• cannot conduct electricity (delocalised electrons are not able to move)

Question 10

Why is C60 known as buckminsterfullerene and what uses does it have?

Answer 10

It is called buckminsterfullerene due to a resemblance to the geodistic domes of Buckminster Fuller
Act as hollow caves to trap other molecules, meaning they can carry drugs around the body and deliver them to where they are needed and trap dangerous substances in the body and remove them.

Question 11

Define a metallic bond

Answer 11

The electrostatic force of attraction between metal cations and delocalised electrons.

Question 12

Give 3 properties of metallic elements and explain them.

Answer 12

• hard solids with high melting points- strong ESFOA
• conduct electricity and heat- delocalised electrons which are able to move
• malleable and ductile- made up of layers which can slide over each other easily