Draw the Lewis structure for XeF
and then answer the following question: How many lone pairs of electrons are around Xe? 0 0 0 1 0 2 0 3 0 4
The Correct Answer and Explanation is:
To draw the Lewis structure for xenon fluoride (XeF₄), follow these steps:
Step 1: Count the total number of valence electrons.
- Xenon (Xe) is in group 18, so it has 8 valence electrons.
- Fluorine (F) is in group 17, and each fluorine atom has 7 valence electrons.
- Since there are 4 fluorine atoms, the total number of valence electrons from fluorine is 4×7=284 \times 7 = 284×7=28.
So, the total number of valence electrons is:8 (from Xe)+28 (from F)=36 valence electrons.8 \text{ (from Xe)} + 28 \text{ (from F)} = 36 \text{ valence electrons.}8 (from Xe)+28 (from F)=36 valence electrons.
Step 2: Create the skeletal structure.
- Xenon (Xe) will be the central atom because it can expand its octet, and fluorine atoms will be placed around it.
Step 3: Distribute electrons.
- Each F atom will form a single bond with Xe, using 2 electrons per bond. This accounts for 4×2=84 \times 2 = 84×2=8 electrons.
Step 4: Complete the octets of the fluorine atoms.
- Each F atom now has 6 remaining valence electrons (since it already shares 2 electrons with Xe). So, place 3 lone pairs on each F atom, using 4×6=244 \times 6 = 244×6=24 electrons.
Step 5: Distribute the remaining electrons around Xe.
- Xenon still needs electrons to complete its octet, but since it’s in period 5, it can have more than 8 electrons. After the 4 bonds (8 electrons) to fluorine, Xenon will have 4 electrons left to form 2 lone pairs.
Step 6: Check the final structure.
- Xenon has 2 lone pairs of electrons and 4 bonds with fluorine atoms. Each fluorine atom has 3 lone pairs.
Final Structure:
rCopyEdit F
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F--Xe--F
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F
How many lone pairs are around Xe?
There are 2 lone pairs of electrons around Xe.
Explanation:
Xenon in XeF₄ has an expanded octet because it is a noble gas in period 5. Xenon can accommodate more than 8 electrons due to the availability of d-orbitals. After bonding with the four fluorine atoms, which each contribute one bonding electron pair, the remaining electrons are placed as lone pairs on xenon. This gives Xenon 2 lone pairs of electrons. The fluorine atoms each have 3 lone pairs to complete their octet.
