The arrangement of electron pairs around the central atom is octahedral and shape is not octahedral and can be identified with the help of presence of lone pair of electrons and bond of electrons associated with the central atom.
The structure ofgiven species are as follows.
In
SF6, the central atom sulphur has 6 valence electrons, which are bonded with
6F -atoms, thus have octahedral shape.
In
XeF6, central atom, Xe has 8 valence electrons, out of which 6 are bonded with 6 F-atoms and one
lp of electron is associated with Xe-atom. Thus, has distorted octahedral shape.
In
BrF5, central atom
(Br) has 7 valence electrons, out of which 5 are bonded with 5 F-atoms and one lp of electron is associated with Br-atom having square pyramidal shape.
In
XeO2F4, central atom, Xe has 8 valence electrons, out of which 4 are bonded through 4 -sigma bonds with 4 F-atams and two oxygen atoms each having one sigma bond and one pi bond is associated with Xe-atom, Thus, has octahedral shape.
Thus, option (3) is correct.