Why is the formal charge on B in BF4- is 1?
Wrong answer man. Your answer got 2 disvotes 👎 in 14 years. That is when I was born🙄
To determine the formal charge on an atom in a molecule, you need to compare the number of valence electrons that the atom initially has (as an isolated atom) with the number of valence electrons it is assigned in the molecule. Here's the step-by-step process to calculate the formal charge on the boron atom (B) in BF4- (tetrafluoroborate ion):
1. Determine the number of valence electrons for each atom:
- Boron (B) is in Group 3 of the periodic table, so it has 3 valence electrons.
- Fluorine (F) is in Group 7, so each fluorine atom has 7 valence electrons.
2. Count the total number of valence electrons in the molecule:
- There are four fluorine atoms in the BF4- ion, so the total number of valence electrons is: 3 (from B) + (4 × 7) (from F) + 1 (for the negative charge) = 32 valence electrons.
3. Assign all the valence electrons to their respective atoms:
- Each bond (except for the last one) between boron and fluorine involves two electrons, so these electrons are assigned to both the B and the attached F atom, as they are shared.
- Each bond leaves a lone pair of electrons on each fluorine atom. Since there are four F atoms, there are four lone pairs of electrons on F.
- The total number of valence electrons used in the bonding is: (4 × 2) + (4 × 2) = 16 electrons.
4. Calculate the formal charge for the boron atom:
- The formula for calculating the formal charge is: Formal Charge = Valence Electrons - (Lone Pair Electrons + 0.5 × Bonding Electrons)
- Valence Electrons for B: 3
- Lone Pair Electrons on B: 0
- Bonding Electrons on B: (4 × 2) = 8
- Substituting these values into the formula, we get: Formal Charge = 3 - (0 + 0.5 × 8) = 3 - 4 = -1.
Therefore, the formal charge on the boron atom (B) in BF4- is -1, not 1.
To determine the formal charge on an atom in a molecule or ion, you need to consider the valence electrons of the atom and the number of bonds it forms along with any lone pairs of electrons it has.
To calculate the formal charge, you can use the formula: Formal Charge = Valence Electrons - Number of Bonds - Number of Lone Pairs.
In the case of B in BF4-, Boron (B) is in Group 13 of the periodic table, which means it typically has 3 valence electrons. In BF4-, there are 3 B-F bonds, which means Boron is involved in 3 bonds. Additionally, Boron does not have any lone pairs of electrons in this molecule.
Using the formula, we can calculate the formal charge on B:
Formal Charge = 3 (valence electrons) - 3 (bonds) - 0 (lone pairs)
Formal Charge = 0
Therefore, the formal charge on B in BF4- is 0, not 1.
If you believe the formal charge on B in BF4- is 1, it is possible there may be an error or other factors that alter the formal charge calculation. Double-check the molecular structure and valence electron count to ensure accuracy.
  F
  ..
F:B:F
  ..
  F
I didn't place the electrons around each F atom because of spacing problems but there are 8 electrons (4 pairs) around B. Count each shared pair as 1 for B. That is 4. It is in group IIIA and has only three in the elemental state. That gives it one more electron than it started with so that is a -1 charge.