In year 12 physics and chemistry or more related, because in physics the topic of Ideas to implementation you will be talking about Sem -conductors and Super Conductors, Semi = talking about Silicon and Germanium and the quantum numbers which will be easy if u learnt chemistry. Quantum numbers is the shells and basically in semi conductors it involves an energy breach from the valance band to conduction band, i will not go in depth with that, but it would make more sense if you did chemistry. In physics next you you will also be discussing crystal lattice structures in superconductors, a topic which is covered in the first module of Chemistry - Both have pros and cons
However if you are good at math, it might be helpful for chemistry
Good luck on your decision