AS: Polarisation and IMFs

Question 1

What is a “Dipole”?

Answer 1

A difference in CHARGE between the 2 atoms caused by a SHIFT in ELECTRON DENSITY in the bond

Question 2

What makes a bond polar?

Answer 2

If the 2 atoms, in a COVALENT bond are of DIFFERENT ELECTRONEGATIVITIES

Question 3

the greater the electronegativity…the more _____ the bond is

Answer 3

POLAR

Question 4

What would happen if you put a ELECTROSTATICALLY CHARGED ROD next to polar liquid (e.g. Water)

Answer 4

Liquid moves TOWARDS the rod cos it contains MOLECULES with PERMANENT DIPOLES. Doesn’t matter if rod is + or - as the polar molecules of liquid can TURN AROUND so it’s always attracted

Question 5

What are the 3 different types of IMF’s?

Answer 5

• Van der Waals Forces
• Permanent Dipole - Dipole Forces
• Hydrogen Bonding

Question 6

Put these in order of strength:

Metallic
IMFs
Covalent

Answer 6

Covalent
Metallic (I think)
IMFs

Question 7

Hydrogen bonding will only happen when Hydrogen is __________ bonded to a ___ element

Answer 7

Covalent

NOF - Nitrogen | Oxygen | Fluorine

Question 8

In Hydrogen bonding, what is attracted to what?

Answer 8

The positive Hydrogen is attracted to the negative lone pair

Question 9

What is the effect of HYDROGEN bonding on:
• MP and BP?
• Density?

Answer 9

• HIGHER MP and BP as EXTRA energy needed to break HYDROGEN bonds
• MORE H BONDS = LESS DENSE