To determine which molecule has the lowest number of unshared electrons on the central atom, we need to consider the valence electrons of the central atom in each molecule and how many of those are involved in bonding with the surrounding atoms.
Let's analyze each molecule step-by-step:
1. XeF4:
- Xenon (Xe) has 8 valence electrons.
- In XeF4, xenon forms 4 bonds with 4 fluorine (F) atoms.
- Each bond uses 1 electron from the xenon, so 4 electrons are used in bonding.
- The remaining unshared electrons are [tex]\(8 - 4 = 4\)[/tex] electrons which form 2 lone pairs.
2. SO2:
- Sulfur (S) has 6 valence electrons.
- In SO2, sulfur typically forms 2 bonds with oxygen (O) atoms.
- Suppose one oxygen forms a double bond, and the other forms a single bond, using a total of 4 electrons in bonding.
- This leaves [tex]\(6 - 4 = 2\)[/tex] unshared electrons or 1 lone pair.
3. ClF3:
- Chlorine (Cl) has 7 valence electrons.
- In ClF3, chlorine forms 3 bonds with 3 fluorine atoms.
- Each bond uses 1 electron from the chlorine, so 3 electrons are used in bonding.
- The remaining unshared electrons are [tex]\(7 - 3 = 4\)[/tex] electrons forming 2 lone pairs.
4. H2O:
- Oxygen (O) has 6 valence electrons.
- In H2O, oxygen forms 2 bonds with hydrogen (H) atoms.
- Each bond uses 1 electron from the oxygen, so 2 electrons are used in bonding.
- The remaining unshared electrons are [tex]\(6 - 2 = 4\)[/tex] electrons forming 2 lone pairs.
5. SF6:
- Sulfur (S) has 6 valence electrons.
- In SF6, sulfur forms 6 bonds with 6 fluorine atoms.
- All 6 valence electrons are used in bonding.
- This leaves [tex]\(6 - 6 = 0\)[/tex] unshared electrons.
From this analysis, we can summarize the number of unshared electrons on the central atom for each molecule as follows:
- XeF4: 4 electrons (2 lone pairs)
- SO2: 2 electrons (1 lone pair)
- ClF3: 4 electrons (2 lone pairs)
- H2O: 4 electrons (2 lone pairs)
- SF6: 0 electrons
Thus, the molecule with the lowest number of unshared electrons around the central atom is SF6.
So, the molecule with the lowest number of unshared electrons around the central atom is SF6.
