Topic 2- Bonding And Structure

Question 1

Definition of ionic bonding

Answer 1

The electrostatic attraction between oppositely charged ions.

Question 2

Define isoelectric

Answer 2

When 2 ions have the same electron configuration

Question 3

Define covalent bond

Answer 3

A strong electrostatic attraction between 2 nuclei and a shared pair of electrons between them

Question 4

Define electronegativity

Answer 4

The ability of an atom to attract the electrons within a covalent bond.

Question 5

What is the name of the shape of a molecule that has a central atom with 5 substiuents?

Answer 5

Trigonal Bipyrimidal

Question 6

Why does HF have a much higher boiling temp than HCl?

Answer 6

• F is highly electronegative
• This creates a strong dipole, making the H have a positive dipole.
• The H attracts lone pairs of electrons in neighbouring molecules.
• HF has hydrogen bonding, HCl doesn’t

Question 7

What is the nature of permanent dipoles?

Answer 7

• occur in polar molecules

- due to a siginificant difference in electronegativity.

Question 8

What is the nature of London Forces?

Answer 8

• occur between all simple covalent molecules

- caused by fluctuations of electron density which induces a dipole

Question 9

Explain 2 factors that affect London forces

Answer 9

• The higher the number of electrons, the greater chance of temporary dipoles forming, making London forces stronger.
• The shapes of molecules. Long alkane chains have greater London forces than branched or spherical alkanes.

Question 10

What is the nature of hydrogen bonding?

Answer 10

• A hydrogen is attached to one of the three most electronegative atoms.
• A lone pair is available
• There is a large electronegativity difference

Question 11

Why does water have a higher boiling point that methane?

Answer 11

• Water has hydrogen bonding and the oxygen has 2 lone pairs on it
• Strong dipoles in water so stronger london forces between molecules.
• Methane has weak London forces.
• Water requires more energy to overcome the intermolecular forces than methane.

Question 12

Define metallic bonding

Answer 12

The electrostatic force between positive ions and their delocalised electrons

Question 13

Name 3 giant covalent lattices

Answer 13

• graphite
• diamond
• silicon oxide

Question 14

why does ice have a lower density than liquid water?

Answer 14

Molecules are held further apart from the hydrogen bonds.

Question 15

Explain the trend of boiling points with increasing alkane chain length

Answer 15

• The longer the alkane chain, the higher the boiling point.
• A larger surface area means more london forces can form.
• So more energy required to overcome these forces.

Question 16

Give the shape and bond angle of a compound with:

2 bonding pairs, 0 lone pairs

Answer 16

Linear, 180

Question 17

Give the shape and bond angle of a compound with:

3 bonding pairs, 0 lone pairs

Answer 17

Trigonal planar

120

Question 18

Give the shape and bond angle of a compound with:

3 bonding pairs, 1 lone pairs

Answer 18

Trigonal pyramidal

107

Question 19

Give the shape and bond angle of a compound with:

4 bonding pairs, 0 lone pairs

Answer 19

Tetrahedral

109.5

Question 20

Give the shape and bond angle of a compound with:

2 bonding pairs, 2 lone pairs

Answer 20

Bent

104.5

Question 21

Give the shape and bond angle of a compound with:

5 bonding pairs, 0 lone pairs

Answer 21

Trigonal Bipryamidal

120 and 90

Question 22

Give the shape and bond angle of a compound with:

6 bonding pairs, 0 lone pairs

Answer 22

Octahedral

90

Question 23

State and explain the shape and bond angle within ammonia

Answer 23

There are 3 bonding pairs and 1 lone pair

• electron pairs repel more than bonding pairs so bond angle is reduced
• shape is trigonal pyramidal and bond angle is 107