Polarizability SiYuan Wu Kyle See Arya Khalesi Reshma Mathew Jordan Howick

What is Polarizability? Polarizability is the ease with which charge distribution is distorted. The greater the polarizability, the more easily the electron cloud can be distorted to create an instantaneous dipole. More polarizable molecules have larger dispersion forces.

Dispersion Influence The strength of a dispersion force depends on the ease with which the charge distribution in a molecule can be distorted. Polarizability usually increases as the number of electrons in an atom or molecule increases. Therefore, the strength of dispersion forces tends to increase with increasing atomic or molecular size.

Polarizability Positively charged ions usually hold onto their electrons tightly due to an excess of proton in the nucleus, so their polarizability is usually quite small. Only larger positively charged ions can be easily polarizable. Negative ions are easily polarizable because they have a larger electron cloud that tends to be more polarizable. Small, positively charged ions can easily distort theses negative ions.

Summary 1. Polarizability defines the molecules ability to become polarized 2. How easily the electron cloud of a molecule is distorted (moving to one side) to create poles (positive and negative). 3. As Polarizability increases, dispersion forces become stronger. Thus, molecules attract towards one another more vigorously and they have higher melting/boiling points which increase with larger molecular mass.

Polarizability Animation Hydrogen_polar.gif