The N/Z (neutron-to-proton) ratio is a measure of the number of neutrons to protons in the nucleus of an atom. The N/Z ratio can vary among different elements and isotopes. However, it's important to note that the exact values can change with ongoing scientific research and discoveries. the element with the lowest N/Z ratio is helium-3 (He-3), and the element with the highest N/Z ratio is hydrogen-1 (H-1), which is simply a proton.
Helium-3 (He-3) has a nucleus composed of two protons and one neutron, resulting in an N/Z ratio of 1/2 or 0.5. On the other hand, hydrogen-1 (H-1) consists of a single proton in its nucleus and lacks any neutrons, thus having an N/Z ratio of 0/1 or 0.
Please keep in mind that scientific understanding and new discoveries can evolve over time, so it's advisable to consult the latest research or reference materials for the most up-to-date information on specific elements and their properties.