Intermolecular Forces

Question 1

Intermolecular forces

Answer 1

A weak force of attraction between molecules, ions or atoms of noble gases

Question 2

Diople-dipole

Answer 2

Attractive forces between polar molecules

Question 3

London Forces/ Induced dipole/dispersion

Answer 3

Non polar molecules combine and their electron clouds repel each other and distort to have slightly changed sides and a momentary dipole is created

Question 4

Special case of dipole-dipole

Answer 4

Hydrogen bonding:
hydrogen is bonded to:
- a small atom
- of high electronegativity (increases surface area, increases boiling point)
- with at least one lone pair of electrons
N2,O2,F2

Question 5

What affects the strength of these forces?

Answer 5

The number of electrons:

1. The molecular mass-larger electron cloud density-more electrons=stronger
2. Surface area- more points of contact-more electrons=stronger

Question 6

Difference between INTRAMOLECULAR forces and INTERMOLECULAR forces?

Answer 6

IMF- weak forces of attraction between molecules, ions or atoms of noble gases

Intramolecular- forces of attraction inside molecules

Question 7

Crystal lattice

Answer 7

The 3D spatial arrangement of the particles in the solid

Question 8

Molecular solids

Answer 8

Made of molecules
London or hydrogen
Soft, low melting points
I2,H20(ice)

Question 9

Network solids

Answer 9

Made of atoms
Have covalent bonds
Graphite and Diamond
Hard, high melting point (overcome strong covalent bonds)

Question 10

Ionic solids

Answer 10

Made of cations and anions
High melting points, brittle
Copper 2 Sulphate, Sodium chloride

Question 11

Metallic solids

Answer 11

Made of positive atomic kernels
It has metallic bonds
Good conductors, high melting points

Question 12

What makes the attractive forces within a crystal lattice strong?

Answer 12

Due to the close proximity of the cations and ions and therefore there is lots of energy required to overcome these attractive forced hence they are very strong