Symbols $_{35}^{79} Br$ and $^{79} Br$ can be written,whereas symbols $_{79}^{35} Br$ and $^{35} Br$ are not acceptable. Answer briefly.

(N/A) The general convention of representing an element along with its atomic mass $(A)$ and atomic number $(Z)$ is $_{Z}^{A} X$.
Hence,$_{35}^{79} Br$ is acceptable because $Z = 35$ and $A = 79$,whereas $_{79}^{35} Br$ is not acceptable as the atomic number of Bromine is $35$,not $79$.
$^{79} Br$ is acceptable as it specifies the isotope,but $^{35} Br$ is not acceptable because the atomic number $35$ is already fixed for Bromine,and the notation should represent the mass number to distinguish isotopes.