Question
VSEPR Notation for BF4-
Answers
GPT-4o mini
The VSEPR (Valence Shell Electron Pair Repulsion) notation for the tetrafluoroborate ion, \( \text{BF}_4^- \), can be understood by analyzing its molecular structure.
1. **Count the total valence electrons**:
- Boron (B) has 3 valence electrons.
- Each fluorine (F) has 7 valence electrons, and there are 4 fluorine atoms: \( 4 \times 7 = 28 \).
- The charge of -1 indicates that there is an additional electron.
- Total = \( 3 + 28 + 1 = 32 \) valence electrons.
2. **Determine the central atom**:
- Boron (B) is the central atom in \( \text{BF}_4^- \).
3. **Assign bonding and non-bonding electrons**:
- Boron forms four single bonds with four fluorine atoms, using 8 electrons in total (2 electrons per bond).
- This leaves no non-bonding electron pairs on boron, and all the fluorine atoms complete their octets by having three lone pairs each.
4. **Molecular geometry**:
- With 4 bonding pairs and no lone pairs on the central atom, the shape is tetrahedral.
The VSEPR notation describes the molecular geometry. For \( \text{BF}_4^- \):
- **VSEPR notation**: AX₄
- A = central atom (B)
- X = surrounding atoms (F)
- 4 = number of surrounding atoms.
Thus, the VSEPR notation for the tetrafluoroborate ion \( \text{BF}_4^- \) is **AX₄**, and the molecular geometry is **tetrahedral**.
1. **Count the total valence electrons**:
- Boron (B) has 3 valence electrons.
- Each fluorine (F) has 7 valence electrons, and there are 4 fluorine atoms: \( 4 \times 7 = 28 \).
- The charge of -1 indicates that there is an additional electron.
- Total = \( 3 + 28 + 1 = 32 \) valence electrons.
2. **Determine the central atom**:
- Boron (B) is the central atom in \( \text{BF}_4^- \).
3. **Assign bonding and non-bonding electrons**:
- Boron forms four single bonds with four fluorine atoms, using 8 electrons in total (2 electrons per bond).
- This leaves no non-bonding electron pairs on boron, and all the fluorine atoms complete their octets by having three lone pairs each.
4. **Molecular geometry**:
- With 4 bonding pairs and no lone pairs on the central atom, the shape is tetrahedral.
The VSEPR notation describes the molecular geometry. For \( \text{BF}_4^- \):
- **VSEPR notation**: AX₄
- A = central atom (B)
- X = surrounding atoms (F)
- 4 = number of surrounding atoms.
Thus, the VSEPR notation for the tetrafluoroborate ion \( \text{BF}_4^- \) is **AX₄**, and the molecular geometry is **tetrahedral**.