Question

Give the formula of a polyatomic ion that you would expect to have the same Lewis structure as (a) \(\mathrm{Cl}_{2}\) (b) \(\mathrm{H}_{2} \mathrm{SO}_{4}\) (c) \(\mathrm{CH}_{4}\) (d) \(\mathrm{GeCl}_{4}\)

Short answer

Question: Identify the polyatomic ions with the same Lewis structure as the given molecules. (a) \(\mathrm{Cl}_{2}\) (b) \(\mathrm{H}_{2} \mathrm{SO}_{4}\) (c) \(\mathrm{CH}_{4}\) (d) \(\mathrm{GeCl}_{4}\) Answer: (a) Hypochlorite ion, \(\mathrm{ClO}^{-}\) (b) Sulfate ion, \(\mathrm{SO}_{4}^{2-}\) (c) Ammonium ion, \(\mathrm{NH}_{4}^{+}\) (d) Tetrachloroaluminate ion, \(\mathrm{AlCl}_{4}^{-}\)

Step-by-step solution

(a) Identifying polyatomic ion with the same Lewis structure as \(\mathrm{Cl}_{2}\)

First, we determine the Lewis structure of \(\mathrm{Cl}_{2}\). Both chlorine atoms have 7 valence electrons and form a single covalent bond. They share one pair of electrons and have 6 remaining lone pairs. Now, we need to find a polyatomic ion that also has a single bond and 6 lone pairs on its atoms. An example of such a polyatomic ion is the hypochlorite ion, \(\mathrm{ClO}^{-}\). In this ion, the oxygen atom has single bonds with a chlorine atom, and it has 6 lone pairs of electrons.

(b) Identifying polyatomic ion with the same Lewis structure as \(\mathrm{H}_{2} \mathrm{SO}_{4}\)

\(\mathrm{H}_{2} \mathrm{SO}_{4}\) is sulfuric acid. We need to find a polyatomic ion with a similar Lewis structure, focusing on the central sulfur atom and its bonding behavior. The sulfate ion, \(\mathrm{SO}_{4}^{2-}\), has the same Lewis structure as the sulfuric acid without the hydrogen atoms. In both cases, the central sulfur atom is connected to four oxygen atoms with double and single bonds and carries an overall charge of 2-.

(c) Identifying polyatomic ion with the same Lewis structure as \(\mathrm{CH}_{4}\)

The Lewis structure of \(\mathrm{CH}_{4}\) features a carbon atom at the center surrounded by four hydrogen atoms. Each hydrogen atom is bonded to the carbon atom via a single bond, and the carbon atom has no lone pairs. A similar polyatomic ion is the ammonium ion, \(\mathrm{NH}_{4}^{+}\). It has a nitrogen atom in the center surrounded by four hydrogen atoms. The nitrogen atom is bonded to each hydrogen atom through a single bond.

(d) Identifying polyatomic ion with the same Lewis structure as \(\mathrm{GeCl}_{4}\)

\(\mathrm{GeCl}_{4}\) has germanium in the center with four chlorine atoms surrounding it. Each chlorine atom is connected to the germanium by a single bond, and the germanium atom has no lone pairs. The tetrahedral molecular geometry of \(\mathrm{GeCl}_{4}\) matches that of the tetrachloroaluminate ion, \(\mathrm{AlCl}_{4}^{-}\). In this ion, aluminum is the central atom, surrounded by four chlorine atoms. Each chlorine atom is bonded to the aluminum atom through a single bond, and aluminum has no lone pairs.