intermolecular forces

Question 1

what are london forces?

Answer 1

electrons move randomly and electron density fluctuates, temporarily creating dipoles which can cause dipoles to be formed in neighbouring molecules called induced dipoles

Question 2

the more electrons in a molecule

Answer 2

the more chance of a temporary dipole forming and the greater the knteraction

Question 3

what other factor increases size of dipole interactions

Answer 3

shape- longer molecules have larger surface area for these interactions to form than spherical ones

Question 4

permanent dipole forces

Answer 4

occur between polar molecules and are stronger than london foxes (hence greater boiling point)

Question 5

hydrogen bonding

Answer 5

strongest intermolecular force, when hydrogen is attached to nitrogen, fluorine or oxygen and this other atom has a lone pair of electrons

Question 6

factors affecting london forces?

Answer 6

no. of electrons- more electrons cause larger temporary dipoles leading to stronger london forces which increases melting/boiling points as it takes more energy to overcome the london forces between molecules

Question 7

2nd factor affecting london forces?

Answer 7

shape of molecules- un branched molecules have more surface contact between them so more london forces between molecules which take more energy to over come (therefore higher melting and boiling points)