Which member in each pair has the greater dispersion forces?(c) SiH4 or GeH4.

Verified step by step guidance

1. Understand that dispersion forces, also known as London dispersion forces, are a type of van der Waals force that occur between all atoms and molecules due to the temporary fluctuations in electron density.
2. Recognize that the strength of dispersion forces generally increases with the size of the electron cloud, which is related to the molar mass and the number of electrons in the molecule.
3. Compare the molar masses of SiH4 and GeH4. Silicon (Si) has a lower atomic mass than Germanium (Ge), so SiH4 will have a lower molar mass than GeH4.
4. Consider the number of electrons in each molecule. GeH4 has more electrons than SiH4 because Germanium has more electrons than Silicon.
5. Conclude that GeH4, having a larger molar mass and more electrons, will have greater dispersion forces compared to SiH4.

Key Concepts

Dispersion Forces

Dispersion forces, also known as London dispersion forces, are weak intermolecular forces arising from temporary fluctuations in electron density within molecules. These fluctuations create instantaneous dipoles that induce dipoles in neighboring molecules, leading to an attractive force. The strength of dispersion forces increases with the size and polarizability of the molecules involved.

Molecular Size and Polarizability

Polarizability refers to the ease with which the electron cloud of a molecule can be distorted by an external electric field or nearby charges. Larger molecules, like GeH4 compared to SiH4, generally have more electrons and a larger electron cloud, making them more polarizable. This increased polarizability results in stronger dispersion forces.

Comparative Analysis of Molecular Structures

When comparing molecular structures, it is essential to consider factors such as atomic size, molecular weight, and the number of electrons. In the case of SiH4 and GeH4, GeH4 has a larger atomic radius and more electrons due to the presence of germanium instead of silicon. This difference contributes to the greater dispersion forces in GeH4 compared to SiH4.