Construct the Lewis structure model for the covalent compound sulfur difluoride (SF2) using the following steps. (1) The number of valence electrons in the sulfur atom is 6. The total number of valence electrons in the two fluorine atoms is 14. Hence, the total number of valence electrons in SF2 is 20. Arrange the atomic cores for the two fluorine atoms with the sulfur atom as the central atom in the space below: Rewrite the atomic cores in the space below: Place an electron pair between each fluorine and sulfur core. (4) Write the Lewis structure for SF2 in the box, distributing the remaining valence electrons so that all three atoms are in accordance with the octet rule. Lewis structure of SF2
The Correct Answer and Explanation is:
Lewis Structure of Sulfur Difluoride (SF₂)
Step-by-step process:
- Determine total valence electrons:
- Sulfur (S) has 6 valence electrons.
- Each fluorine (F) atom has 7 valence electrons.
- Total from 2 fluorines = 2 × 7 = 14
- Total valence electrons = 6 + 14 = 20 electrons
- Arrange the atomic cores:
Place sulfur in the center and fluorine atoms on each side since sulfur is less electronegative and can form more than one bond. rCopyEditF S F - Place a single electron pair (bond) between sulfur and each fluorine:
Each single bond uses 2 electrons, so:- 2 bonds × 2 electrons = 4 electrons used
- Remaining: 20 – 4 = 16 electrons left
- Distribute remaining electrons to satisfy the octet rule
- Place 6 electrons (3 lone pairs) on each fluorine to complete their octets.
- 2 fluorines × 6 electrons = 12 electrons
- Remaining: 16 – 12 = 4 electrons le Place the remaining 4 electrons as 2 lone pairs on sulfur.
- Check octet rule:
- Fluorine atoms: each has 2 bonding electrons + 6 nonbonding = 8 (satisfied)
- Sulfur atom: 2 bonds (4 electrons) + 4 nonbonding = 8 electrons (satisfied)
Final Lewis Structure of SF₂:
rCopyEdit ..
:F:—S—:F:
..
- Each fluorine has three lone pairs.
- Sulfur has two lone pairs.
- Two single bonds between S and each F.
Explanation:
The Lewis structure is a method of representing molecules by showing how valence electrons are arranged among atoms. For sulfur difluoride (SF₂), this structure helps illustrate the bonding and nonbonding electron pairs.
We begin by counting all the valence electrons. Sulfur belongs to group 16 and has 6 valence electrons. Each fluorine atom, found in group 17, has 7. With two fluorine atoms, this totals 14 electrons. Together with sulfur’s 6, the molecule has a total of 20 valence electrons to be distributed.
Next, we determine the skeletal structure. Sulfur, being the less electronegative atom and capable of forming multiple bonds, is placed at the center, with each fluorine atom on either side. We then form single bonds between sulfur and each fluorine, which accounts for 4 electrons.
We are left with 16 electrons. These are then used to satisfy the octet rule, which states that atoms prefer to have eight electrons in their valence shell. Each fluorine atom needs 6 more electrons (3 lone pairs) to complete its octet. Once that is done, 4 electrons remain, which are assigned as two lone pairs on sulfur.
The resulting structure ensures that all atoms follow the octet rule. Each fluorine has 8 electrons (2 from the bond with sulfur, and 6 as lone pairs), and sulfur also has 8 electrons (4 from bonds and 4 as lone pairs). This structure accurately represents the electron distribution in SF₂ and reflects its bent molecular shape due to the two lone pairs on the sulfur atom, which repel the bonded fluorine atoms.
