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.

it takes on an electronical energy

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.