Intermolecular forces

Question 1

What are the three types of van der waals?

Answer 1

London dispersiom, dipole-dipole, hydrogen bonds

Question 2

How do london dispersion form?

Answer 2

• instantaneous movement of electrons in one molecule results in an instantaneous dipole
• this induces a temporary dipole in a neighbouring molecule
• delta + end of one molecule is attracted to the delta - end in the other molecule

Question 3

How do dipole-dipole form?

Answer 3

• large difference in electronegativity between 2 adjacent molecules results in partial charges (more electronegative pulls bonding pair of electrons towards itself more)
• this causes the bond to be polar
• delta + end of one molecule is attracted to the delta - end in the other molecule

Question 4

How do H bonds form?

Answer 4

• occur when a N, O or F are directly bonded to a H
• these are atoms that highly electronegative and pull the bonding pair of electrons towards itself that much that they expose the nucleus of the hydrogen atom, which has a very strong + charge
• this attracts the delta - N, O or F on the neighbouring molecule