Question

1. this is a diagram of ammonia. this molecule has a central nitrogen atom singly bonded to three hydrogen atoms. the nitrogen atom also has one lone pair of electrons. the shape of this molecule can be classified as _______. a) linear b) trigonal planar c) tetrahedral d) trigonal pyramidal

Explanation:

To determine the molecular shape of ammonia (\(NH_3\)):

1. First, identify the electron - domain geometry. The central nitrogen atom has 3 bonding domains (from the three \(N - H\) bonds) and 1 non - bonding domain (the lone pair of electrons). The total number of electron domains is \(3 + 1=4\), so the electron - domain geometry is tetrahedral.
2. Then, determine the molecular shape. The molecular shape is determined by the arrangement of the bonding domains (ignoring the lone pair for shape description, but the lone pair still influences the shape). With 3 bonding domains and 1 lone pair, the atoms (hydrogen atoms) are arranged in a trigonal pyramidal shape.

• A linear shape (option A) has a bond angle of \(180^{\circ}\) and 2 bonding domains, which is not the case for \(NH_3\).
• A trigonal planar shape (option B) has 3 bonding domains and no lone pairs, with bond angles of \(120^{\circ}\), which does not match \(NH_3\) as it has a lone pair.
• A tetrahedral shape (option C) is the electron - domain geometry when there are 4 bonding domains (no lone pairs), like in \(CH_4\), but \(NH_3\) has a lone pair, so it's not tetrahedral in molecular shape.
• The trigonal pyramidal shape (option D) is characteristic of a molecule with a central atom having 3 bonding domains and 1 lone pair, which is the case for \(NH_3\).

Answer:

D) trigonal pyramidal