hi i have a question about nuclear spin if the number of protons and neutrons is even, then my chemistry book says, that the nuclear spin is always zero. i guess that the reason is, that there are always 2 protons and 2 neutrons in one state with opposite spin and therefore the overall spin is zero, so that's all right for me. but then: if the number of protons and neutrons is odd, then my chemistry book says, that the nuclear spin is some number like 1,2,3,4 and so on. how so? i mean, if i have let me say 19 protons and 9 neutrons, then there are 18 protons that give me zero spin(after the first rule) and 8 neutrons that give me zero spin(also after the first rule) therefore i would say, that this proton and neutron could give me only 1, but not 2 or more...or are these rules not correct or where am i wrong?