To draw the Lewis dot structure for sulfur tetrafluoride (SF4), start by counting the valence electrons. Sulfur (S) has 6 valence electrons, and each fluorine (F) has 7 valence electrons. Since there are four fluorine atoms, the total number of valence electrons is:
6 (from S) + 4 × 7 (from F) = 6 + 28 = 34 valence electrons.
In the Lewis structure, sulfur acts as the central atom, surrounded by four fluorine atoms. Each S-F bond uses 2 electrons, totaling 8 electrons for four bonds. Thus, we use 8 of the 34 total valence electrons, leaving us with 26 electrons to place around the fluorine atoms.
Each fluorine atom needs 3 additional electrons to complete its octet, using a total of 12 electrons (3 electrons for each of the four fluorine atoms), which leaves us with 14. The remaining 14 electrons are placed as 3 lone pairs on sulfur.
Now, we can summarize the properties of SF4:
- a. Number of bond pairs: There are 4 bond pairs between sulfur and the fluorine atoms.
- b. Number of lone pairs: There are 1 lone pair on the sulfur atom.
- c. Molecular geometry: The molecular geometry of SF4 is seesaw, due to the presence of the lone pair, which alters the arrangement of the four bonded fluorine atoms.
- d. Hybridization of the central atom: The hybridization of the central atom (sulfur) is sp³d, as it uses one s orbital, three p orbitals, and one d orbital to form the bonds and accommodate the lone pair.