What is lowest to highest radiation energy

E α particles > E β particles > E γ rays , where E= energy

Explanation:

When an unstable atomic core disintegrates due to its instability , a particle emission called radioactive decay – or radiation energy - occurs (this occurs when there is an excess of energy)

There are, basically, 3 types of radiation energy:

-Alpha particles (α): these are Helium particles, with just 2 protons and 2 neutrons. Alpha particles have the most mass, for which its capacity to penetrate all materials is quite limited (they don´t pass through a thin sheet of paper or body´s skin)

Alpha particles have a high amount of energy

-Beta particles (β): these are electrons (e-) or positrons (e+), and have a much less mass than Alpha particles, for which they have more capacity to penetrate all materials (they can penetrate a sheet of paper, however, they are not able to penetrate a thin sheet of metal

These particles have much less energy than Alpha particles

-Gamma rays (γ): these are electromagnetic radiations, hence they don´t have mass nor energy, and so they are able to penetrate all materials (actually, it is necessary to use a thick cement wall to stop this type of rays)

So, considering the energy (E) for the above description:

E α > E β > E γ rays

You may also have another perspective (when it comes to energy) using the following formula:

E=mc² which it let us see that energy is directly proportional to mass (the more mass, the more energy)