molecular geometry quiz

📚 Quick Study Guide

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• VSEPR Theory: Valence Shell Electron Pair Repulsion theory states that electron pairs around a central atom will arrange themselves to minimize repulsion.
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• Basic Shapes: Linear, trigonal planar, tetrahedral, trigonal bipyramidal, and octahedral are the fundamental molecular geometries.
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• Bonding vs. Lone Pairs: Lone pairs exert greater repulsive force than bonding pairs, affecting bond angles.
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• Determining Geometry: Count the number of bonding pairs and lone pairs around the central atom to determine the electron-pair geometry, then consider the arrangement of atoms to find the molecular geometry.
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• Bond Angles: Ideal bond angles for common geometries: Tetrahedral ($109.5^{\circ}$), Trigonal Planar ($120^{\circ}$), Linear ($180^{\circ}$).
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• Impact of Lone Pairs on Bond Angle: Each lone pair reduces the bond angle by approximately $2.5^{\circ}$ in tetrahedral molecules.

🧪 Practice Quiz

1. Which of the following molecular geometries has bond angles of 120°?
   1. Linear
   2. Tetrahedral
   3. Trigonal Planar
   4. Bent
2. What is the molecular geometry of $CO_2$?
   1. Bent
   2. Linear
   3. Trigonal Planar
   4. Tetrahedral
3. The molecular geometry of $H_2O$ is:
   1. Linear
   2. Bent
   3. Tetrahedral
   4. Trigonal Pyramidal
4. What is the electron-pair geometry of $NH_3$?
   1. Trigonal Planar
   2. Tetrahedral
   3. Trigonal Pyramidal
   4. Bent
5. Which of the following molecules is tetrahedral?
   1. $BF_3$
   2. $H_2O$
   3. $CH_4$
   4. $NH_3$
6. Which of the following statements about lone pairs is correct?
   1. Lone pairs do not affect molecular geometry.
   2. Lone pairs increase bond angles.
   3. Lone pairs have less repulsive force than bonding pairs.
   4. Lone pairs decrease bond angles.
7. What is the molecular geometry of $SF_6$?
   1. Tetrahedral
   2. Octahedral
   3. Trigonal Bipyramidal
   4. Square Planar