Nuclei with an _____________ number of protons and neutrons possess a property called spin. Nuclear spin can be thought as either up or down with the spin states normally possessing _________ energy levels while generating equal but opposite _________ When a molecule is placed in an NMR, a large ________ field is applied making the spin states become of unequal energy, with the spin that generates a magnetic field in the same direction of the applied magnetic field being ___________ in energy. The NMR then uses _________ to 'flip the spin' of each nuclei, wherein each nuclei will require a specific energy level of radiation that corresponds to its difference in energy of spin states, this is often called the nuclei's __________ frequency, which is measured by the NMR and translated to teh final spectra.