1.4

Question 1

What is a covalent bond?

Answer 1

A shared pair of electrons with opposed spins between two atoms

Question 2

What is a co-ordinate bond?

Answer 2

covalent bond where both
electrons come from one of
the atoms

Question 3

What is an ionic bond?

Answer 3

Formed by the electrostatic attractions between the cations and anions after one atom gives one or more electrons to the other

Question 4

What is the name given to many ions together

Answer 4

Solid lattice

Question 5

How is ionic bonding energetically possible

Answer 5

Although energy is needed to form the ions it is repaid by the strong electrical attraction between the cation and anion

Question 6

Describe the attractive and repulsive forces within a covalent bond

Answer 6

Electrons in the pair repel each other

Overcome by their attractions to both nuclei

Question 7

Describe how an ionic bond is structured due to attractive and repulsive forces

Answer 7

Ions are arranged so each cation is surrounded by many anions and vice versa
Maximises attraction
Minimises repulsion

Question 8

What is electronegativity

Answer 8

The measure of the ability of an atom in a covalent bond to attract the electron bonding pair

Question 9

How is bond polarity governed

Answer 9

Difference in electronegativity value

Question 10

Most electronegative atoms

Answer 10

F O N

Question 11

What is a dipole

Answer 11

Separation of charge in a molecule

One part is partially negative and another partially positive

Question 12

How do dipoles arrange themselves

Answer 12

Negative region of one molecule is close to the positive region of another molecule so that there is a net attraction between them

Question 13

What are Van der Waals forces

Answer 13

Weak intermolecular forces

Question 14

2 types of van der waals forces

Answer 14

Dipole-dipole

Induced dipole-induced dipole

Question 15

What is a hydrogen bond

Answer 15

a relatively strong intermolecular bond having a hydrogen atom joined to a very electronegative element in a molecule and bonding to another electronegative element in another molecule.

Question 16

Why is hydrogen bonding stronger than that of van der Waals forces

Answer 16

Small hydrogen is sandwiched between 2 electronegative element which allows close approach

Question 17

Which is longer in a diagram showing hydrogen bonding - the hydrogen bond or intramolecular bond?

Answer 17

Hydrogen

Question 18

What shape is given to ice and why

Answer 18

Tetrahedral

Oxygen has 2 lone pairs and Hydrogen has 2 atoms

Question 19

Describe the trend in boiling temperatures of intermolecular bonding

Answer 19

• increase with strength of forces
• VDW - steady increase with molecular mass and larger dipoles
• H bonds much higher boiling temperature than VDW of similar sized molecules

Question 20

What is a bonding pair?

Answer 20

two electrons having opposed spins that bond two atoms in a molecule together by a covalent or co-ordinate
bond.

Question 21

What is a lone pair?

Answer 21

two elections having opposed spins that belong to one atom only and are not involved in bonding to another atom

Question 22

What are the principles of the VSEPR theory

Answer 22

1. Shape of molecules are governed by the electron pairs around the central atom
2. Electron pairs repel each other as far away as possible to minimise repulsion
3. lp-lp>lp-bp>bp-bp

Question 23

Name, angle and example of molecule with 2 electron pairs

Answer 23

Linear
180
BeCl2

Question 24

Name, angle and example of molecule with 3 electron pairs

Answer 24

Trigonal planar
120
BF3

Question 25

Name, angle and example of molecule with 4 bonding pairs

Answer 25

Tetrahedral
109.5
CH4

Question 26

Name, angle and example of molecule with 5 electron pairs

Answer 26

Trigonal bipyramidal
90/120
PCl5

Question 27

Name, angle and example of molecule with 6 electron pairs

Answer 27

Octahedral
90
SF6

Question 28

Name and angle of molecule with 3 bonding pairs and 1 lone pair

Answer 28

Trigonal pyramidal

107

Question 29

Name, angle and example of molecule with 2 bonding pairs and 2 lone pairs

Answer 29

Angular, bent
104.5
Water

Question 30

What is a solute

Answer 30

The substance that dissolves in the solvent

Question 31

What is a solvent

Answer 31

Liquid medium in which the solute dissolves

Commonly water

Question 32

What is a saturated solution

Answer 32

One that cannot dissolve any more solute under the existing conditions

Question 33

What is a polar molecule

Answer 33

Molecule with some separation of positive and negative charge

Question 34

Does oil dissolve in water - why

Answer 34

No
Will form separate layers
Water - H bonding
Hydrocarbons- VDW

Question 35

Why do alcohols dissolve in water providing the hydrocarbon chain is not too long

Answer 35

Hydrogen bonding is present in both molecules

Question 36

Why does water dissolve inorganic salts eg NaCl

Answer 36

There is a strong interaction between the ions in the salt and the water dipoles

Question 37

How does water dissolve a polar molecule

Answer 37

Oxygen regions of water molecules align themselves around the cations
Hydrogen regions of water align themselves around the anions
The attractions of these are enough to pull the ions from the solid lattice so that it dissolves