Nuclear stability is the function of ratio of neutron to proton.If the number of neutrons is higher than is required for stability of the nucleus, the nucleus becomes unstable.
In order to gain stability, it would try to convert this extra mass of neutrons into sub-particles which are thrown out of the atom. This is done to achieve stability.When this happens naturally it is called as natural radioactive decay.Over 60 radionuclides are found naturally and classified as primordial and cosmogenic and are found in soil, air and water around us.
yes
yes
Thorium, plutonium and iron are radioactive (be sure, the natural isotope 54Fe is radioactive !).
Radon is a natural radioactive gas.
Yes, uranium is a natural but radioactive element.
Zirconium does have radioactive isotopes, but the main ones used in industry are not radioactive.
no... omg
Hydrogen has only one natural radioactive isotope(3H), of cosmogenic origin, but only in ultratraces on the earth. Sodium has two radioactive natural isotopes (22Na and 24Na), of cosmogenic origin, but only in ultratraces on the earth. Oxygen has not natural radioactive isotopes. All the isotopes of uranium are radioactive.
Yes, a natural isotope can be radioactive. Some natural isotopes have unstable nuclei and undergo radioactive decay to achieve a more stable form. This process involves the emission of radiation in the form of alpha particles, beta particles, or gamma rays.
No, trace elements are not necessarily radioactive. A link to a list of elements that have no natural radioactive isotopes is at a related question, below.
Uranium is a natural, radioactive metal.
Depleted uranium is approx. 60% less radioactive than an equivalent mass of natural uranium.