Element : relates to the number of protons in an atom. (Element 12 = Carbon atom, which has 12 protons). Each element may have isotopes, which are different kinds of atoms having the same number of protons. They differ by the number of neutrons.
A molecule is a group of atoms. A quanta is a minimal unit of energy. For example, a molecule may rotate at x revs/second, at x+1 revs/ second, but not at x + 1/2 revs / a second, because then it would have to lose half a quanta which is impossible according to quantum mechanics.
A particle can be anything that is small. Often, it is the smallest possible thing in your field of study. An ion is an atom with too many or too few electrons, making it charged (+ or -).
An atom has a nucleus, which is surrounded by electrons. The nucleus is made of protons (+) and neutrons (neutral). Protons and neutrons are themselves made of 3 quarks.
A photon is practically the same as a quanta. If a molecule loses a quanta of energy, it emits a photon having this same energy. In the case of a glow-in-the-dark watch needle, the photons are detected by your eyes as green light.
