What is the half-life of every radioactive element?
The same element can have different half-lives, for different isotopes. You can find a list at the Wikipedia article "List of radioactive isotopes by half-life". This list is NOT complete; a complete list would have about 3000 nuclides (that is, isotopes).
All atoms of a specific element have the same number of protons in their nucleus, but the number of neutrons in the nucleus may vary these are isotopes of that element. Hydrogen has several possible isotopes, only the first three of these are commonly referred to: hydrogen or protium or hydrogen-1, 1 proton 0 neutrons, stable deuterium or hydrogen-2, 1 proton 1 neutron, stable tritium or hydrogen-3, 1 proton 2 neutrons, radioactive halflife 12.26 years…
Whether an ISOTOPE (not element) is naturally radioactive depends not only on the number of protons, but also on the number of neutrons. For EVERY element, there are radioactive isotopes.There has to be a certain relationship between the number of protons and the number of neutrons, but the relationship isn't a simple one.