Structure & Bonding

Question 1

What are the structures of each chemical bond?

Answer 1

Ionic: Giant ionic lattice
Covalent: Simple covalent, giant covalent
Metallic: Giant metallic lattice

Question 2

Describe the structure of a giant ionic lattice

Answer 2

An ionic compound is a giant structure of ions. The ions have a regular, repeating arrangement called an ionic lattice.

The lattice is formed because the ions attract each other and form a regular pattern with oppositely charged ions next to each other.

An ionic lattice is held together by strong electrostatic forces of attraction between the oppositely charged ions. The forces act in all directions in the lattice.

Question 3

What are the properties of an ionic compound?

Answer 3

• Crystalline solids
• Can be dissolved or molten
• Hard and brittle
• Can only conduct electricity when dissolved or molten
• High melting and boiling points

Question 4

Why are ionic compounds crystalline?

Answer 4

Because of the strong electrostatic interaction between these oppositely charged ions, ionic compounds form rigid crystals.

Question 5

Why do ionic compounds have high melting and boiling points?

Answer 5

The ionic compounds are usually hard because the ions are held by strong force of attraction as the positive and negative ions are strongly attracted to each other and difficult to separate.

Question 6

Why can ionic compounds only conduct electricity when molten or dissolved?

Answer 6

Ionic compounds conduct electricity when molten, because their ions are free to move from place to place.

Ionic compounds cannot conduct electricity when solid, as their ions are held in fixed positions and cannot move.

Question 7

What is the difference between giant covalent and simple covalent compounds?

Answer 7

The key difference is that simple covalent molecules have a small and fixed number of atoms, while giant structures have large and variable numbers of atoms.

Question 8

Describe the structure of simple covalent bond

Answer 8

There are strong covalent bonds between atoms that form molecules together. However, there are weak intermolecular forces between the molecules.

Question 9

What are the properties of a simple covalent substance

Answer 9

• Cannot conduct electricity
• Low melting and boiling points
• Don’t dissolve in water

Question 10

Why can’t simple molecules conduct electricity?

Answer 10

The molecules have a neutral charge so they can’t conduct electricity and there are no electrons that are free to move

Question 11

Why do simple molecules have low melting and boiling points?

Answer 11

They have relatively low melting points and low boiling points because the molecules are held together by weak intermolecular forces that break down easily.

Question 12

What are the properties of giant covalent structures?

Answer 12

• High melting and boiling points
• Most compounds don’t conduct electricity however some do.

Question 13

What is an allotrope?

Answer 13

Allotropes are different forms of the same element, in the same state.

Question 14

Describe the structure of diamond

Answer 14

• Giant covalent structure
• Each carbon atom is bonded to 4 other carbon atoms
• Has a tetrahedral 3D structure

Question 15

What are the properties of diamond and what are its uses

Answer 15

• High melting and boiling points
• Doesn’t conduct electricity
• Hard
• Used to cut through metals, rocks and glass

Question 16

Describe the structure of graphite

Answer 16

• Each carbon atom forms three covalent bonds with 3 other atoms
• Forms layers of hexagonal rings
• Weak forces of attraction between layers
• There is one delocalised electron for each atom

Question 17

What are the properties of graphite and its uses

Answer 17

• High melting and boiling points
• Good electrical conductivity
• Soft
• Lubricant
• Pencils

Question 18

What are the properties of graphene

Answer 18

• High melting and boiling points
• Good electrical conductivity
• Very strong

Question 19

What is the structure of a giant metallic lattice?

Answer 19

Metals are giant lattices of positive ions arranged in regular layers, with delocalised electrons free to move throughout the structure.

Question 20

What are the properties of giant metallic structures?

Answer 20

• High melting and boiling points
• Good electrical conductivity
• Malleable and ductile

Question 21

Why do giant metallic substances have high melting and boiling points?

Answer 21

High temperatures are required to break strong metallic bonds.

Question 22

Why do giant metallic substances have good electrical condcutivity?

Answer 22

Metal’s delocalised electrons can move and carry charge.

Question 23

Why are giant metallic substances malleable and ductile?

Answer 23

Metal’s layers of ions can slide over each other, but are still held together by the delocalised electrons. This means metal is malleable (it can be hammered into shape) and ductile (it can be drawn out into wires)