Is a carbon atom spontaneously lost a proton what element would be formed

Protons carry a positive electrical charge and they alone determine the charge of the nucleus. Adding or removing protons from the nucleus changes the charge of the nucleus and changes that atom's atomic number. So, adding or removing protons from the nucleus changes what element that atom is!

Explanation: For example, adding a proton to the nucleus of an atom of hydrogen creates an atom of helium. (Actually, a few neutrons have to be added as well to make the new nucleus stable, but the end result is still helium.) Keep in mind that atoms, by definition, are electrically neutral and always contain the same number of protons and electrons.