Intermolecular Forces

Question 1

Describe the valence shell electron pair repulsion (VSEPR) theory

Answer 1

A model used to predict 3D molecular geometry based on the number of valence shell electron bond pairs among the atoms in a molecule or ion

Electron pairs in the valence shell of the central atom of a molecule will stay as far apart as possible to minimize the electrostatic repulsion between electron pairs in the valence shell

Question 2

Describe and explain polarity

Answer 2

When an entity contains two distinct and opposite poles that can either attract or repel each other

Question 3

Describe a polar molecule

Answer 3

Molecules that have a polar bond and the shapes are asymmetrical as a result of a dipole

Question 4

Describe a non-polar molecule

Answer 4

Either have no polar bond or have polar bonds but are symmetrical in shape therefore cancelling each other

Question 5

Describe vapour pressure

Answer 5

Measure of the tendency of a material to change into the gaseous or vapour state

Question 6

Describe dispersion forces

Answer 6

Dispersion forces are also known as London dispersion forces and are generally weaker than dipole-dipole forces

Temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles

Dispersion forces exist between all molecules and result from the attractions between instantaneous dipoles and induced dipoles

Question 7

Describe dipole-dipole attractions

Answer 7

Dipole-dipole forces exist between polar molecules which have permanent dipoles

Question 8

Describe hydrogen bonding

Answer 8

A special type of dipole-dipole attraction that occurs between the lone pair of a highly electronegative atom and the hydrogen atom in a N–H, O–H, or F–H bond