VSEPR Theory and Molecular Shapes

The video tutorial covers the VSEPR theory, focusing on determining molecular shapes based on electron pairs and bonds around a central atom. It provides detailed explanations and practice problems for various molecules, including PF3, NO2, NO3, OF2, HCN, NH4, SBH3, ozone, and SC2. The tutorial emphasizes the importance of understanding the basic shapes like tetrahedral, trigonal planar, and linear, and how lone electron pairs affect bond angles and molecular geometry.

What is the first step in determining the VSEPR shape of a molecule?

• Identify the number of lone pairs on the central atom.

• Count the total number of atoms in the molecule.

• Determine the number of things around the central atom.

• Calculate the molecular weight.

In a trigonal pyramidal shape, how do lone pairs affect bond angles compared to a tetrahedral shape?

• They decrease the bond angles.

• They increase the bond angles.

• They make the bond angles exactly 120°.

• They have no effect on bond angles.

What is the VSEPR shape of NO2?

• Linear

• Bent

• Trigonal planar

• Tetrahedral

How does the presence of a charge on a molecule like NO3- affect its VSEPR shape?

• It has no impact on the VSEPR shape.

• It doubles the bond angles.

• It makes the shape linear.

• It changes the shape to bent.

What is the molecular shape of OF2?

• Tetrahedral

• Bent

• Trigonal planar

• Linear

In a linear molecule like HCN, what is the bond angle between the atoms?

• 90°

• 120°

• 180°

• 109.5°

What is the VSEPR shape of NH4+?

• Trigonal pyramidal

• Tetrahedral

• Bent

• Linear

How many lone pairs are present in the VSEPR shape of SBH3?

• Three

• One

• Two

• None

What is the shape of ozone (O3) according to VSEPR theory?

• Linear

• Tetrahedral

• Trigonal planar

• Bent

In SC2, how do the lone pairs affect the molecular shape?

• They have no effect.

• They result in a bent shape.

• They create a trigonal planar shape.

• They make it linear.