• # question_answer 77)   Explain the shape of $Br{{F}_{5}}$

Shape of $\mathbf{Br}{{\mathbf{F}}_{\mathbf{5}}}$ Br-atom has configuration : $1{{s}^{2}},2{{s}^{2}}2{{p}^{6}},3{{s}^{2}}3{{p}^{6}}3{{d}^{10}},4{{s}^{2}}4{{p}^{5}}$ To get pentavalency, two of the p-orbitals are unpaired and electrons are shifted to 4d-orbitals. In this excited state $s{{p}^{3}}{{d}^{2}}$-hybridisation occurs giving octahedral structure. Five positions are occupied by F atoms forming sigma bonds with hybrid bonds and one position occupied by lone pair i.e., the molecule as a square pyramidal shape.