Question

consider nitrogen trichloride, ncl₃. the lewis structure has 3 single bonds and one nonbonding electron pair. the number of reds is 1. the bond angles are 2° and the shape is 3. ncl₃ is a 4 symmetrical/asymmetrical molecule. a. 0 b. 1 c. 2 d. 3 e. 4 f. 180 g. 90 h. 120 i. 109.5 j. diatomic k. linear k. planar trigonal m. bent n. pyramidal o. tetrahedral p. symmetrical q. asymmetrical

Explanation:

• Number of REDs (Region of Electron Density): The formula for REDs is \( \text{Number of bonds (single, double or triple)}+\text{Number of non - bonding electron pairs}\). Here, there are 3 single bonds and 1 non - bonding electron pair. So, \(3 + 1=4\).
• Bond angles: For a molecule with 4 REDs (where 1 is a non - bonding pair), the electron - pair geometry is tetrahedral (\(109.5^{\circ}\) ideal bond angles for tetrahedral electron - pair geometry). But due to the lone pair - bond pair repulsion (lone pair occupies more space), the bond angle is slightly less than \(109.5^{\circ}\). However, if we consider the VSEPR model for the electron - pair geometry (ignoring the fact that one is a lone pair for the purpose of bond - angle assignment based on the formula), the bond angle is \(109.5^{\circ}\).
• Shape: When there are 3 bonding pairs and 1 non - bonding pair of electrons around the central atom (\(N\) in \(NCl_3\)), the molecular shape is pyramidal (also called trigonal pyramidal).
• Symmetry: Since there is a non - bonding electron pair, the molecule is asymmetrical. The dipoles do not cancel out.

Answer:

E. 4, I. 109.5, N. pyramidal, Q. asymmetrical