Prior to 2013, this was an external standard - AS90522 Atoms, Photons and Nuclei. It is likely to be assessed using an internal test from 2013 onwards (although teachers can select from a range of assessment techniques - see the BIG notes).
There were only minor changes to this existing material in the standard when it became AS91525 but also a number of additions including Relativity and material on fundamental particles.
The old external examinations may be useful revision for an internal test.
91525 Demonstrate understanding of Modern Physics BIG notes- needs additional material for fundamental particles (almost complete)
Last minute Atoms - needs additional material for Relativity and fundamental particles