Particle X is responsible for moving and the transfer of energy.
In a metal, it is the electrons that are free to move and transfer energy. These are often referred to as delocalized electrons. They can move throughout the metal’s structure, allowing electrical charge and thermal energy to be conducted.
So, in the diagram provided, particle X, which represents an electron, is the one that is free to move and transfer energy. Particle Y, which represents a nucleus, is not free to move as it is fixed in place within the metal lattice.
This is a fundamental property of metals that contributes to their ability to conduct electricity and heat.