I need to explain this with regards to the metallic bond. It would also be good if you could explain why certain metals are sonorous and others aren't.
The metallic bond is a delocalised connection meaning that the electron cloud is free to move - as a result the dissipation of energy in metals is very low, so when struck the energy is caught in a damping effect causing the metal to resonate
I however am not sure why some metals don't show this property - I was thinking that density had a role (as group 1 metals arn't sonorous) but then realised that lead (very dense) isn't sonorous either