Select the Lewis structure for XeO2F2 which correctly minimizes formal charges. Show formal charges on each atom and that of the overall.
The Correct Answer and Explanation is :
To determine the Lewis structure for XeO₂F₂, we need to first consider the number of valence electrons in the molecule and how to distribute them to minimize formal charges.
Step 1: Count the valence electrons
- Xenon (Xe) is in Group 18, so it has 8 valence electrons.
- Oxygen (O) is in Group 16, so each oxygen atom has 6 valence electrons. There are two oxygen atoms, giving 12 valence electrons.
- Fluorine (F) is in Group 17, so each fluorine atom has 7 valence electrons. There are two fluorine atoms, giving 14 valence electrons.
The total number of valence electrons is:
- Xe: 8
- O₂: 12
- F₂: 14 Total = 8 + 12 + 14 = 34 valence electrons.
Step 2: Set up the skeletal structure
- Xenon (Xe) is the central atom because it is the least electronegative and can expand its octet.
- Place the two oxygen atoms and the two fluorine atoms around Xenon.
Step 3: Distribution of electrons
- Start by forming bonds between the atoms. Each O and F will bond with Xenon (Xe).
- Oxygen atoms will typically form double bonds with the central atom to complete their octet, while fluorine atoms will form single bonds.
Step 4: Minimize formal charges
Now, we check the formal charges on each atom to make sure they are minimized. The formal charge can be calculated using the formula: Formal charge=Valence electrons−(Lone pair electrons+Bonding electrons2)\text{Formal charge} = \text{Valence electrons} – (\text{Lone pair electrons} + \frac{\text{Bonding electrons}}{2})
By calculating the formal charges for each atom:
- Xenon typically has a formal charge of 0 since it can share electrons efficiently.
- Each oxygen in a double bond will have a formal charge of 0.
- Each fluorine, with a single bond and three lone pairs, will also have a formal charge of 0.
Step 5: Result
The Lewis structure is as follows:
- Xenon in the center, with double bonds to the two oxygen atoms and single bonds to the two fluorine atoms.
- Each oxygen atom has two lone pairs, and each fluorine atom has three lone pairs.
This structure minimizes the formal charges, with all atoms having a formal charge of 0.
I’ll now generate the image of this structure.
Here is the Lewis structure for XeO₂F₂, where Xenon is in the center, bonded to two oxygen atoms (with double bonds) and two fluorine atoms (with single bonds). The formal charges on all atoms are 0. This structure minimizes formal charges, with each atom having its proper number of electrons and bonds.
