Do the electron configuration of both atoms.
Ti:
Atomic number 22.
Abbreviated electron configuration: [Ar] 3d^2 4s^2
Valence electrons 4s^2
Hf:
Atomic number: 72
Abbreviated electron configuration: <span>[Xe] 4f^14 5d^2 6s<span>^2</span></span>
The subshells that behave as valence orbitals are, generally, those of the highest energy level.
In this case those are 6s.
Answer: 6s
Br2 is the correct answer
Can u try putting this in english please