The concept of reducing the various forces they have encountered in physics down to four fundamental forces often proves to be challenging as does the array of new particles they are exposed to in the particle physics section.
Often a strong historical timeline can help the students appreciate that the particle were discovered over time and theories had to evolve to explain the observations.
It builds upon their study of radioactivity from GCSE.
The study of particle physics enables students to discuss the cutting edge of physics and where will the next ten years lead us in terms of our understanding of matter.
They are expensive; governments have to make difficult decisions when building new ones.
The building of nuclear power stations can be used to evaluate the benefits and risks to society (HSW9).
This one on Physics Net provides a good overall summary (see 'Particle interactions').The schoolphysics site has a good treatment of logarithmic graphs (see 'Mathematical consideration of radioactive decay').