Topic 1.3 - Bonding

Question 1

Define ion

Answer 1

When an atom loses or gains electrons

Question 2

What is ionic bonding?
What is its structure?
What forces are there?

Answer 2

Metals + non-metals
Structure: Giant ionic lattice
Forces: Strong electrostatic

Question 3

What are three properties of ionic bonding?

Answer 3

• Electrical conductivity > Yes (when molten or dissolved) as ions are free to move and can carry charge
• Melting point > High
  > lots of energy needed to overcome strong electrostatic forces
• Solubility > Dissolve in water
  > Water molecules pull ions away from the lattice as they are trapped polar

Question 4

What is covalent bonding?
What is its structure?
What forces does it have?

Answer 4

Between non-metals
Structure: Simple covalent
Forces: Weak intermolecular

Question 5

What are three properties of covalent bonding?

Answer 5

• Electrical conductivity > No
  > No delocalised electrons to carry charge
• Melting point > Low
  > Little energy needed to break weak forces
• Solubility > Depends on how polarised molecules are

Question 6

Which three compounds have a giant covalent structure?
What is its structure?
What are the forces?

Answer 6

• Graphite
• Diamond
• Silicon dioxide
  Structure: Giant structure
  :Sheets of hexagons
  : Each carbon atom forms three bonds
  Forces: Weak forces between layers
  : Strong covalent bonds between carbon atoms

Question 7

What are the two properties of giant covalent structure?

Answer 7

• Conduct electricity > No (except graphite as it has delocalised electrons)
• Melting point > High
  > Lots of energy needed to break strong covalent bonds

Question 8

What are the four properties of graphite?

Answer 8

Electrical conductivity > Yes
> Fourth bond becomes a delocalised electron
Melting point > High
> Strong covalent bonds in hexagonal sheets
Insoluble > Covalent bonds in sheets are too difficult to break
Soft > Weak bonds between layers are easily broken
> Sheets slide over each other

Question 9

What is the structure and bonding of diamond?

Answer 9

Structure > Tetrahedral shape
> Each carbon atom forms four bonds
> Giant structure
Bonds > Strong covalent bonds

Question 10

What are the four properties of diamond?

Answer 10

Melting point > High
> Lots of energy needed to break strong covalent bonds
Electrical conductivity > No
Hard > Giant structure
Insoluble > Covalent bonds are too difficult to break

Question 11

Define co-ordinate / dative covalent bond

Answer 11

One atom provides both of the shared electrons

Question 12

What is metallic bonding between?
What structure does it have?
What bonding does it have?

Answer 12

• Between metals
• Structure: Giant metallic lattice
• Forces: electrostatic attraction

Question 13

What are the four properties of metallic bonding?

Answer 13

• Melting point > High
  > Strong electrostatic attraction between positive metal ions and negatively charged delocalised electrons
• Electrical conductivity > Yes
  > Delocalised electrons can carry charge
• Solubility > Insoluble
  > Strong metallic bonds
• Malleable / ductile > Metal ions slide over each other

Question 14

What three things increase metallic bonding?

Answer 14

• Greater charge on ions
• More delocalised electrons
• Smaller metal ion

Question 15

What are the two types of electron pairs?
Which electron pair repels more?

Answer 15

• Bonding pairs (shared electrons)
• Lone pairs (unshared electrons)

Lone pairs repel more than bonding pairs. This affects shape of molecule

Question 16

What is the shape and bond angle when there are 2 bonding pairs and 0 lone pairs?

Answer 16

Shape: Linear
Bond angle: 180•

Question 17

What is the shape and bond angle when there are 3 bonding pairs and 0 lone pairs?

Answer 17

Shape: Trigonal planar
Bond angle: 120•

Question 18

What is the shape and bond angle when there are 2 bonding pairs and 1 lone pair?

Answer 18

Shape: Bent
Bond angle: 118•

Question 19

What is the shape and bond angle when there are 4 bonding pairs and 0 lone pair?

Answer 19

Shape: Tetrahedral
Bond angle: 109.5•

Question 20

What is the shape and bond angle when there are 3 bonding pairs and 1 lone pair?

Answer 20

Shape: Trigonal pyramidal
Bond angle: 107•

Question 21

What is the shape and bond angle when there are 2 bonding pairs and 2 lone pairs?

Answer 21

Shape: Bent
Bond angle: 104.5•

Question 22

What is the shape and bond angle when there are 5 bonding pairs and 0 lone pairs?

Answer 22

Shape: Trigonal bipyramidal
Bond angle: 120• and 90•

Question 23

What is the shape and bond angle when there are 4 bonding pairs and 1 lone pair?

Answer 23

Shape: Seesaw
Bond angle: 102• and 86.5•

Question 24

What is the shape and bond angle when there are 3 bonding pairs and 2 lone pairs?

Answer 24

Shape: T-shape
Bond angle: 87.5•

Question 25

What is the shape and bond angle when there are 6 bonding pairs and 0 lone pairs?

Answer 25

Shape: Octahedral Bond angle: 90•

Question 26

What is the shape and bond angle when there are 5 bonding pairs and 1 lone pair?

Answer 26

Shape: Square pyramid Bond angle: 89•

Question 27

What is the shape and bond angle when there are 4 bonding pairs and 2 lone pairs?

Answer 27

Shape: Square planar Bond angle: 90•

Question 28

Define electronegativity

Answer 28

The power of an atom to attract the pair of electrons in a covalent bond

Question 29

What are the three factors that affect electronegativity of an atom?

Answer 29

- Nuclear charge - Atomic radius - Electron shielding

Question 30

On the periodic table, what is the trend in electronegativity across a period and down a group?

Answer 30

Across period = Increases Down group = Decreases

Question 31

What are the three types of intermolecular forces?

Answer 31

- Van der Waals - Permanent dipole - dipole - Hydrogen bonding

Question 32

Which molecules have Van der Waals forces?

Answer 32

- All molecules have Van der Waals forces - Electrons are distributed unevenly - Induces a temporary dipole in neighbouring molecule which produces a temporary induced dipole - dipole attraction Larger molecules = stronger Van der Waals forces

Question 33

Which molecules have permanent dipole - dipole forces?

Answer 33

If the charge of the molecule doesn’t cancel out or molecule is not symmetrical

Question 34

What molecules have hydrogen bonding?

Answer 34

Only when hydrogen is covalently bonded to fluorine, nitrogen or oxygen *Very electronegative

Question 35

What is the order of strength of intermolecular forces in increasing order?

Answer 35

- Van der Waals forces - Permanent dipole - dipole - Hydrogen bonding