Question

what is the hybridization of the central atom in the tribromide (br₃⁻) anion?

Explanation:

Step1: Determine the central atom

The central atom in $Br_3^-$ is a bromine atom.

Step2: Calculate the number of electron - pair groups

The number of bonding pairs ($BP$) and lone - pairs ($LP$) around the central $Br$ atom needs to be determined. The central $Br$ atom has 2 bonding pairs (it is bonded to 2 other $Br$ atoms) and 3 lone pairs. So the total number of electron - pair groups ($n$) is $BP + LP=2 + 3=5$.

Step3: Relate electron - pair groups to hybridization

The number of hybrid orbitals is equal to the number of electron - pair groups around the central atom. When $n = 5$, the hybridization is $sp^3d$.

Answer:

$sp^3d$