What is the molecular geometry of the sulfate ion, SO42−? bent tetrahedral trigonal planar trigonal pyramidal
The Correct Answer and Explanation is :
The correct molecular geometry of the sulfate ion (( \text{SO}_4^{2-} )) is tetrahedral.
Explanation:
- Structure of Sulfate Ion:
The sulfate ion consists of one sulfur atom (( \text{S} )) centrally located, surrounded by four oxygen atoms (( \text{O} )). The sulfur atom is bonded to each oxygen atom through single covalent bonds. - Valence Electrons:
To determine the geometry, we first count the valence electrons. Sulfur has six valence electrons, and each oxygen has six, totaling 24 valence electrons (6 from sulfur + 4 × 6 from oxygen). However, since the sulfate ion has a ( -2 ) charge, we add 2 more electrons, giving us a total of 26 valence electrons. - Lewis Structure:
In the Lewis structure of ( \text{SO}_4^{2-} ), sulfur is at the center with four oxygen atoms bonded to it. Each oxygen atom is connected to sulfur with a single bond, and to satisfy the octet rule for oxygen, each oxygen atom carries a negative charge, forming a resonance structure. There are four equivalent resonance structures, indicating that the double bonds can be distributed among the oxygen atoms. - Molecular Geometry:
The arrangement of the bonded pairs (single bonds in this case) around the sulfur atom leads to a tetrahedral geometry. The ( \text{SO}_4^{2-} ) ion has four regions of electron density (the four S-O bonds), and according to VSEPR (Valence Shell Electron Pair Repulsion) theory, these regions will arrange themselves as far apart as possible, resulting in a tetrahedral shape. - Conclusion:
This tetrahedral arrangement is typical for a species with a central atom bonded to four other atoms with no lone pairs, leading to bond angles of approximately ( 109.5^\circ ). Thus, the molecular geometry of the sulfate ion is best described as tetrahedral.