Final answer:
Bromine, the central atom in BrF3, has two lone pairs according to its Lewis structure, which predicts its electron domain geometry.
Step-by-step explanation:
The central atom of BrF3, bromine, has two lone pairs. This can be determined using the Lewis structure approach, which helps us visualize the electron distribution around atoms in a molecule. According to the structure, BrF3 has five electron groups around the central bromine atom; three of these are bonding pairs with fluorines, and the remaining two are lone pairs. Since the lone pairs contribute to the electron domain but do not form bonds, they are not directly visible in the molecular structure, but they significantly affect the molecular shape, predicting a trigonal bipyramid arrangement.