Energy per photon v. energy per atom

[William_Hora_2H]

I remember from lecture that E in E=hv represent the energy per photon. In the screenshot I attached, particularly Q5B, why is energy represented per atom, namely, 8.0*10^-17 J/1 atom Cu.

[Charmaine Ho 2G]

8 x 10^-17 J represents the energy emitted by one excited copper atom at 1.2 x 10^17 Hz. In Q5B, it asks for how much energy is produced in 2 mol of Cu atoms. To convert from energy per Cu atom to mol, you multiply 8 x 10^-17 J/Cu atom x 6.022x10^23 Cu atom/mol x 2mol

[605537776]

That is the answer because the question is asking "by a copper atom".