2.2.2 Bonding and Structure (ionic and covalent bonding)

Question 1

What are the three main types of bonding?

Answer 1

• ionic
• covalent
• metallic

Question 2

What is ionic bonding?

Answer 2

the electrostatic attraction between positive and negative ions

Question 3

Give an example of an ionically bonded substance

Answer 3

NaCl (sodium chloride - salt)

Question 4

What is a compound ion?

Answer 4

An ion which is made of multiple atoms

Question 5

What structure do ionic compounds have?

Answer 5

A lattice structure

Question 6

What is a giant ionic lattice structure?

Answer 6

A structure made of repeating units of identical structure

Question 7

State the three properties of ionic compounds?

Answer 7

1. They dissolve in water
2. They conduct electricity
3. They have high melting and boiling points

Question 8

Why do ionic compounds have high melting and boiling points?

Answer 8

As a lot of energy is required to break the strong electrostatic force of attraction between the oppositely charged ions

Question 9

Why do ionic compounds dissolve in water?

Answer 9

• water is a polar solvent
• polar water molecules break down the lattice and surround each ion to form a solution

Question 10

In what type of solvents do ionic lattices dissolve in?

Answer 10

Polar solvents, e.g. water

Question 11

When can ionic compounds conduct electricity?

Answer 11

• When melted or dissolved in water (liquid or aqueous)

Question 12

Why can’t ionic compounds conduct electricity in the solid state?

Answer 12

As the ions are in fixed positions in the giant ionic lattice

Question 13

Why can ionic compounds conduct electricity in the liquid/aqueous state?

Answer 13

As the ionic lattice is broken down when melted or dissolved in water, so the ions are free to move/mobile and can freely carry a charge

Question 14

What does the principle of electroneutrality state?

Answer 14

that the overall charge of a compound ion must be 0

Question 15

Electrons in which shell are represented in dot and cross diagrams?

Answer 15

The outer shell

Question 16

What is A covalent bond?

Answer 16

A shared pair of electrons

Question 17

What is covalent bonding?

Answer 17

the strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms

Question 18

Are covalent or ionic bonds stronger?

Answer 18

covalent, usually

Question 19

Why are covalent bonds strong?

Answer 19

As the shared electrons are attracted to the nucleus of both atoms

Question 20

Are multiple bonds or single bonds in covalent bonding stronger?

Answer 20

multiple bonds

Question 21

What is average bond enthalpy?

Answer 21

A measure of average energy needed to break the covalent bond

Question 22

How many covalent bonds does carbon and oxygen form?

Answer 22

Carbon: 4
Oxygen: 2

Question 23

What is formed when atoms share two pairs of electrons?

Answer 23

A double bond

Question 24

What are the 2 different types of covalent structures that you can have?

Answer 24

1. Simple molecular substances
2. Giant covalent lattices

Question 25

What is a simple molecular lattice?

Answer 25

it is made up of simple molecules, e.g. H2, H20

Question 26

Describe the bonding in simple molecular substances?

Answer 26

atoms within the same molecule are held by strong covalent bonds and different molecules are held by weak intermolecular forces

Question 27

What is an example of a molecule?

Answer 27

Cl2, H20

Question 28

What is an example of a diatomic molecule?

Answer 28

Cl2, H2

Question 29

What is an example of an atom?

Answer 29

Cl

Question 30

What structure do simple molecules form in the solid state?

Answer 30

A regular structure called a simple molecular lattice

Question 31

What are the molecules held together by in a simple molecular lattice?

Answer 31

• weak intermolecular forces, while the atoms are bonded together by strong covalent bonds

Question 32

What are the three properties of simple molecular lattices?

Answer 32

1. Low melting and boiling points
2. Insoluble in water
3. Do not conduct electricity

Question 33

Why do simple molecular substances have low melting and boiling points?

Answer 33

because not much energy is needed to break the weak intermolecular forces

Question 34

Explain the property of solubility

Answer 34

• Non-polar molecules are insoluble in polar substances, but soluble in non-polar
• Polar molecules are insoluble in non-polar substances, but soluble in polar substances

Question 35

Why do simple molecular substances not conduct electricity?

Answer 35

• As there are no free charged particles (ions or electrons) in simple molecular structures
• so there is nothing to carry a charge

Question 36

What is a giant covalent lattice?

Answer 36

A structure where many billions of atoms are held together by a network of strong covalent bonds

Question 37

What are the 4 giant covalent lattices you need to be aware of?

Answer 37

1. Diamond
2. Graphite
3. Graphene
4. Silicon Dioxide (sillica)

Question 38

State two properties of giant covalent lattices?

Answer 38

1. High melting points
2. Insoluble in most solvents

Question 39

Why do giant covalent lattices have high melting points?

Answer 39

As high temperatures are necessary to provide the energy required to break the many strong covalent bonds in the lattice structure

Question 40

Why are giant covalent lattices insoluble in almost all solvents?

Answer 40

As the bonds are far too strong to be broken by interaction with solvents

Question 41

What is a dative covalent bond?

Answer 41

A covalent bond in which both electrons in the bond come from one atom

Question 42

What can dative covalent bonding also be referred to as?

Answer 42

Coordinate bonding