Which electrons have the most energy in an atom

 The  electron  that    have  the  most  energy   in an  atom    is

electrons  in  the   outer  most  shell

Explanation

Electrons  in the outer shell  have  higher  energy  and  they travel  fur from  the  nucleus  than those   in the  inner shells.

As  the  electrons   move away  form the  nucleus   its  energy  become less  and  less  negative,  that  is  their energy   increases.