Question

When determining molecular structure for multi-center molecules, we focus on the:

Answer 1

In multi-center molecules, we focus on the local structures of interior atoms, using steps such as drawing the Lewis structure, determining electron group arrangements, assigning AXmEn designations, and describing the molecular geometry to predict the overall shape.

Step-by-step explanation:

When determining molecular structure for multi-center molecules, we focus on the local structures of the atoms in the molecule. Because larger molecules are composed of a chain of interior atoms rather than a single central atom, understanding each atom's local geometry is essential in predicting the molecule's overall shape. The local geometries are influenced by factors such as bond angles, which are the angles between two bonds including a common atom, and bond distances, which refer to the distance between the nuclei of two bonded atoms.

This strategy for determining molecular structure involves the following steps:

1. Draw the Lewis electron structure of the molecule or polyatomic ion.
2. Determine the electron group arrangement around each central atom to minimize repulsions.
3. Assign an AXmEn designation and identify any LP-LP (lone pair-lone pair), LP-BP (lone pair-bonding pair), or BP-BP (bonding pair-bonding pair) interactions to predict any deviations in bond angles.
4. Describe the molecular geometry of each central atom.

Using these steps allows us to predict the structure of complex molecules such as methyl isocyanate (CH3-N=C=O). By looking at each central atom individually and applying the VSEPR model, we can derive the arrangement and connection of atoms in a molecule.