The mass difference between the pair of mirror nuclei $${}_6^{11}C$$ and $${}_5^{11}B$$ is given to be Δ MeV/c<sup>2</sup>. According to the semi-empirical mass formula, the mass difference between the pair of mirror nuclei $${}_9^{17}F$$ and $${}_8^{17}O$$ will approximately be (rest mass of proton m<sub>p</sub> = 938.27 MeV/c<sup>2</sup> and rest mass of neutron m<sub>n</sub> = 939.57 MeV/c<sup>2</sup>)