This answer is not correct. Each halogen atom (bromine and fluorine) brings 7 electrons to the molecule. There is a total of 42 electrons in all for the electron-dot formula. You are correct in saying that each fluorine atom forms a bond with the bromine atom for 5 pairs of bonding electrons. Each fluorine atom will also have 3 pairs of non-bonding electrons. Thus 40 electrons are used in conjunction with the fluorine atoms. The remaining 2 electrons must go to the bromine atom for 1 non-bonded pair of electrons on bromine.