Question

Select all the statements that correctly describe how to determine the molecular shape of a species using VSEPR:

1: Count the total number of valence electrons in the molecule.
2: Determine the central atom in the molecule.
3: Consider the number of lone pairs of electrons on the central atom.
4: Use the molecular weight of the atoms involved.

Answer 1

To determine molecular shape using VSEPR, count valence electrons, identify the central atom, consider lone pairs, and determine the Lewis structure, regions of electron density, and corresponding hybridized orbitals. Molecular weight doesn't directly affect VSEPR analysis.

Step-by-step explanation:

To determine the molecular shape of a species using Valence Shell Electron Pair Repulsion (VSEPR) theory, the following statements are correct:

• Count the total number of valence electrons in the molecule.
• Determine the central atom in the molecule.
• Consider the number of lone pairs of electrons on the central atom.

However, using the molecular weight of the atoms involved is not a direct step in determining the molecular shape using VSEPR.

To predict the molecular geometry:

1. Determine the Lewis structure of the molecule.
2. Determine the number of regions of electron density around the central atom. Single bonds, multiple bonds, and lone pairs each count as one region of electron density.
3. Assign the set of hybridized orbitals that corresponds to the determined electron geometry.

The shape of a molecule significantly impacts its physical properties and chemical reactivity. The Lewis structure helps illustrate the connections between atoms and the placement of lone pairs, but it does not define bond angles or exact shapes. VSEPR theory takes over from here, predicting molecular shapes based on electron pair repulsions that dictate the overall geometry.