2. Bonding & Structure

Question 1

What is Ionic Bonding?

Answer 1

The strong electrostatic attractions between oppositely charged ions

Question 2

How are cations formed?

Answer 2

Metals lose electrons to form positively charged cations

Question 3

How are anions formed?

Answer 3

Non-metals gain electrons to form negatively charged anions

Question 4

What are the two factors that affect ionic bond strength?

Answer 4

• ionic radius
• ionic charge

Question 5

How does ionic radius affect ionic bond strength?

Answer 5

Smaller ions can pack closely together, strengthening the electrostatic force.
Larger ions weaken the attraction

Question 6

How does ionic charge affect bond strength?

Answer 6

Greater ionic charge leads to stronger electrostatic attraction between ions

Question 6

Which groups on the periodic table lose electrons to form ions?

Answer 6

Groups 1-3

Question 7

Which groups on the periodic table gain electrons to form ions?

Answer 7

Groups 5-6

Question 7

When do ions form?

Answer 7

When atoms gain or lose electrons to achieve a full outer electron shell

Question 8

What do dot and cross diagrams show?

Answer 8

They represent the transfer of electrons during ion formation, using different symbols for each atom’s electrons.

Question 9

Describe the structure of an ionic compound

Answer 9

A giant ionic lattice of alternating anions and cations

Question 10

List four properties of ionic compounds?

Answer 10

• High melting point
• High tensile strength
• Conduct electricity when molten or dissolved
• Soluble in water but insoluble in non-polar solvents

Question 11

Why do ionic compounds conduct electricity when molten or dissolved but not when solid?

Answer 11

Ions are mobile in molten/aqueous so they are able to carry a charge, but fixed in a solid lattice

Question 12

Explain the trend in ionic radius as you go down a group?

Answer 12

Ionic radius increases as we go down a group, due to electron shells increasing.

Question 13

What are isoelectric ions?

Answer 13

Ions that have the same number of electrons but different number of protons

Question 14

What is the trend in ionic radius across isoelectric ions as proton number increases?

Answer 14

As the proton number increases, the ionic radius decreases

Question 15

Why does the ionic radius decrease as proton number increases in isoelectric ions?

Answer 15

A higher proton number creates a stronger nuclear attraction, pulling electrons closer to the nucleus, making the ion smaller.

Question 16

What is Covalent Bonding?

Answer 16

The electrostatic attraction between nuclei and a shared pair of electrons

Question 17

In covalent bonding, what happens to the outer electron shells of atoms?

Answer 17

Atoms share electrons to achieve a full outer shell and greater stability

Question 18

What do dot and cross diagrams represent in covalent bonding?

Answer 18

They show the sharing of electrons

Question 19

What is dative bonding (coordinate bonding)?

Answer 19

The shared pair of electrons in a covalent bond come from only one of the bonding atoms

Question 20

Give two examples of species that show dative bonding

Answer 20

Aluminium chloride dimer (Al₂Cl₆)

Ammonium ion (NH₄⁺)

Question 21

What is the relationship between bond length and bond strength in covalent bonds?

Answer 21

Longer bonds are weaker
Shorter bonds are stronger

Question 22

Why are shorter bonds stronger?

Answer 22

The share electrons are closer to the nuclei, leading to stronger electrostatic attraction

Question 23

What determines the shape of a simple molecule or ion?

Answer 23

The repulsion between electron pairs surrounding the central atom

Question 24

How do lone pairs affect molecular shape?

Answer 24

Lone pairs repel more strongly than bonding pairs, distorting shapes

Question 25

What is metallic bonding?

Answer 25

The electrostatic attraction between positive metal ions and negative delocalised electrons

Question 26

What structure do metals form?

Answer 26

Giant metallic lattice

Question 27

What are the properties of metallic substances?

Answer 27

- High melting/boiling points - Conduct electricity - Malleable and ductile

Question 28

What structures are considered giant lattices - list the main three?

Answer 28

- Giant ionic lattices - Giant covalent lattices - Giant metallic lattices

Question 29

What structure do simple covalent substances like Iodine and Ice have?

Answer 29

Simple molecular structure

Question 30

What are the different carbon structures?

Answer 30

Diamond Graphite Graphene

Question 31

Give the structure and properties of diamond

Answer 31

- Each carbon is bonded 4 times in a tetrahedral shape - A highly packed, rigid arrangement allows heat to conduct well - Very high melting point due to many strong covalent bonds - Does not conduct electricity well - Insoluble

Question 32

Give the structure and properties of Graphite

Answer 32

- Each carbon is bonded to three others in a hexagonal shape - Layers easily slide over each other, as there are weak forces between layers - Conductor of electricity due to delocalised electrons between layers - High melting point due to strong covalent bonds

Question 33

Give the structure and properties of Graphene

Answer 33

- 2D sheet of graphite - One atom thick - Hexagonal carbon rings - Conducts electricity

Question 34

What is electronegativity?

Answer 34

The ability of an atom to attract itself to a bonding pair of electrons from a covalent bond

Question 35

What happens when there is a difference in electronegativity between two atoms?

Answer 35

A polar bond forms, with partial positive and negative charges

Question 36

Why might a molecule with polar bonds still be non-polar overall?

Answer 36

If the shape is symmetrical, dipoles cancel out

Question 37

What are the three types of intermolecular forces?

Answer 37

London forced (induced dipole-induced dipole) Permanent dipole-dipole interactions Hydrogen bonding

Question 38

What are London forces?

Answer 38

Weak attractions due to temporary dipoles from electron movement

Question 39

What are permanent dipole interactions?

Answer 39

Attractions between molecules with permanent dipoles

Question 40

What is a hydrogen bond?

Answer 40

Strong attraction between a hydrogen atom bonded to N, O, or F and a lone pair on another N, O, or F atom

Question 41

What molecules have hydrogen bonding?

Answer 41

Water (H₂O) Ammonia (NH₃) Hydrogen fluoride (HF)

Question 42

Why does water have unusually high melting/boiling points?

Answer 42

Strong hydrogen bonding between water molecules

Question 43

Why is ice less dense than water?

Answer 43

The molecules in ice are held further apart by the hydrogen bonds than in liquid water

Question 44

How does chain length affect boiling point of alkanes?

Answer 44

Longer chains = stronger london forces = higher boiling points

Question 45

How does branching affect alkane boiling points?

Answer 45

More branching = weaker london forces = lower boiling points

Question 46

Why do alcohols have higher melting points than similar alkanes?

Answer 46

Alcohols can form hydrogen bonds

Question 47

What is the trend in boiling points from HF to HI?

Answer 47

HF has a higher boiling point due to hydrogen bonds HI has the highest boiling point due to strong London forces (size effects)

Question 48

Why does water dissolve in ionic compounds?

Answer 48

Water hydrates and stabilises ions through ion-dipole interactions

Question 49

Why does water dissolve simple alcohols?

Answer 49

Through hydrogen bonding between water and the -OH group

Question 50

Why is water a poor solvent for halogenoalkanes?

Answer 50

Halogenoalkanes cannot form hydrogen bonds with water

Question 51

When are non-aqueous solvents used?

Answer 51

When solutes and solvents have similar types of intermolecular forces