FC9: Intermolecular Forces

Question 1

What is electronegativity’s across a period and down a group excluding hydrogen and noble gases?

Answer 1

Increases across, decreases down with Fluorine the most electronegative element

Question 2

What is electronegativity?

Answer 2

The ability of an atom to attract the bonding electrons in a covalent bond

Question 3

When does hydrogen bonding occur?

Answer 3

When H is covalently bonded to N, O or F.

Question 4

Permanent dipole-dipole:-

Answer 4

Unsymemetrical molecules = polar, individual dipoles don’t cancel and so has a permanent dipole, leading to permanent dipole-dipole forces.

Question 5

Non polar molecule:-

Answer 5

Symmetrical, dipoles cancel.

Question 6

Induced dipole-dipole:-

Answer 6

Random electron movements cause an instantaneous dipole in a nearby molecule. There is an attractive force between the dipoles. Weak and temporary.