BF₃ is planar and electron deficient compound. Hybridization and number of electrons around the central atom, respectively are :

To determine the hybridization and the number of electrons around the central atom in boron trifluoride (${\mathrm{BF}}_3$), we can analyze its chemical structure step-by-step.

Step 1: Identify the central atom and its valence electrons
In ${\mathrm{BF}}_3$, the central atom is boron ($B$). Boron belongs to Group 13 of the periodic table, so it has 3 valence electrons in its outermost shell.

Step 2: Determine the bonding and hybridization
Boron shares its 3 valence electrons with 3 fluorine atoms to form 3 single covalent bonds ($\sigma$-bonds). There are no lone pairs of electrons left on the boron atom.
We can calculate the steric number to find the hybridization:
Steric Number = (Number of $\sigma$-bonds) + (Number of lone pairs on central atom)
Steric Number = 3 + 0 = 3
A steric number of 3 corresponds to ${\mathrm{sp}}^2$ hybridization, which gives the molecule a trigonal planar geometry.

Step 3: Calculate the total number of electrons around the central atom
Since boron forms 3 covalent bonds and each covalent bond consists of 2 shared electrons, the total number of electrons in the valence shell of boron in ${\mathrm{BF}}_3$ is:
3 bonds × 2 electrons/bond = 6 electrons
Because the boron atom is surrounded by only 6 valence electrons instead of a stable octet (8 electrons), it is classified as an electron-deficient compound.

Therefore, the hybridization is ${\mathrm{sp}}^2$ and the number of electrons around the central boron atom is 6.