3.1.3.7 Forces between molecules

what forces do all simple covalent molecules have

intermolecular

what 3 types of intermolecular forces are there

van Der walls, dipole-dipole, hydrogen

what is the weakest intermolecular force

van der walls

what forms a van der walls force

an instantaneous dipole due to electron distribution

why does electron distribution induce dipole

electrons repel

what can increase strength of van der walls

more electrons

what molecules have van der walls

all molecules

what forms a dipole-dipole force

permanent attraction between molecules due to electronegativity and bond polarity

what must the element be to have dipole-dipole

asymmetrical

why do symmetrical molecules not have dipole-dipole

polar bonds cancel out

what is the strongest type of inter molecular forces

hydrogen bonds

how strong are intermolecular forces

weak

what elements must be present for a hydrogen bond

hydrogen and fluorine, oxygen or nitrogen

what are hydrogen bonds

direct bonds with hydrogen and a highly electronegative element

does a lone pair affect hydrogen bonding

no

what angle must hydrogen bonds be drawn at

180 degrees

what is melting point affected by

strength of intermolecular bonds