You could choose any element to use in a particle accelerator, but the most commonly-used one is Hydrogen- it's the smallest, the lightest, and most abundant of all elements.
There are 3 parts to an atom:1. Protons2. Neutrons3. ElectronsThe electrons are the smallest of the 3 and therefor weigh the least.A proton is composed of 2 up quarks and 1 down quark while a neutron...