Nanoparticles of a metal are used in a face cream. The same metal in bulk is known to be safe to use on the skin.
Why can the safety data for the metal in bulk not be used for the nanoparticles?
The nanoparticles contain a different element from the bulk metal
The nanoparticles have a much lower density than the bulk metal
The nanoparticles may have different properties from the bulk metal
The nanoparticles are used in a much smaller mass than the bulk metal
40 exam-style questions on AQA GCSE Chemistry 2.4 Bulk and surface properties of matter including nanoparticles, covering 2.4.1 Sizes of particles and their properties and 2.4.2 Uses of nanoparticles. Each one has a worked solution and a mark scheme showing where the marks go.