How many shared electrons are there in the Lewis structure of SbF3?
How many shared electrons are there in the Lewis structure of SbF3?
The Correct Answer and Explanation is:
Answer:
There are 6 shared electrons in the Lewis structure of SbF₃.
Explanation
Antimony trifluoride (SbF₃) is a covalent compound composed of one antimony (Sb) atom and three fluorine (F) atoms. In its Lewis structure, we examine how electrons are distributed to satisfy the octet rule and determine how many electrons are shared between atoms via covalent bonds.
Step 1: Count valence electrons
- Sb (Group 15) has 5 valence electrons.
- F (Group 17) has 7 valence electrons, and there are 3 fluorine atoms.
→ Total from fluorines = 3 × 7 = 21 valence electrons - Total valence electrons in SbF₃ = 5 (Sb) + 21 (F) = 26 electrons
Step 2: Determine bonding
In the Lewis structure:
- Sb forms three single covalent bonds with each of the three fluorine atoms.
- Each single bond consists of 2 shared electrons.
→ Total shared electrons = 3 bonds × 2 electrons = 6 shared electrons
Step 3: Assign lone pairs
After forming the three Sb–F bonds (6 electrons), we have 20 electrons left (26 total – 6 shared = 20).
- Each fluorine atom requires 3 lone pairs (6 electrons) to complete its octet.
→ 3 fluorines × 6 electrons = 18 electrons - The remaining 2 electrons go as a lone pair on Sb.
Final Structure:
- Sb is at the center with three single bonds to fluorine atoms.
- Each F has 6 non-bonding electrons (3 lone pairs).
- Sb has one lone pair.
Summary:
- Number of shared electrons = 6 (from 3 single bonds)
- These shared electrons are what make up the covalent bonds holding SbF₃ together.
This understanding is crucial for predicting molecular geometry (SbF₃ is trigonal pyramidal) and the polarity of the molecule.
