Question

True or false: (a) The more polarizable the molecules, the stronger the dispersion forces between them. (b) The boiling points of the noble gases decrease as you go down the column in the periodic table. (c) In general, the smaller the molecule, the stronger the dispersion forces. (d) All other factors being the same, dispersion forces between molecules increase with the number of electrons in the molecules.

Short answer

(a) True: More polarizable molecules have stronger dispersion forces due to easily distorted electron clouds and stronger temporary dipoles. (b) False: Boiling points of noble gases increase down the periodic table due to stronger dispersion forces from increased atomic size and electrons. (c) False: Larger molecules have stronger dispersion forces due to more electrons and larger electron cloud, resulting in greater polarizability. (d) True: Dispersion forces increase with the number of electrons when all other factors are equal, as larger electron clouds lead to greater polarizability and stronger temporary dipoles.

Step-by-step solution

(a) The more polarizable the molecules, the stronger the dispersion forces between them.

This statement is true. Dispersion forces, also known as London dispersion forces or van der Waals forces, are weak intermolecular forces that arise due to temporary fluctuations in electron density in molecules. More polarizable molecules have more easily distorted electron clouds, leading to stronger temporary dipoles and stronger dispersion forces between them.

(b) The boiling points of the noble gases decrease as you go down the column in the periodic table.

This statement is false. The boiling points of noble gases actually increase as you go down the column in the periodic table. This is because as the atomic size increases, the dispersion forces become stronger due to the increased number of electrons and larger electron cloud. Greater dispersion forces result in higher boiling points.

(c) In general, the smaller the molecule, the stronger the dispersion forces.

This statement is false. In general, the larger the molecule, the stronger the dispersion forces. Larger molecules have more electrons and a larger electron cloud, resulting in greater polarizability and stronger dispersion forces.

(d) All other factors being the same, dispersion forces between molecules increase with the number of electrons in the molecules.

This statement is true. When all other factors are equal, an increase in the number of electrons in the molecules leads to stronger dispersion forces. More electrons result in a larger electron cloud, increasing the polarizability of the molecules and causing stronger temporary dipoles and stronger dispersion forces.