Radioactive+Isotopes

__Answer__:
Yes, almost all of the elements have radioactive isotopes, with the exception of a few of the manmade elements, such as Unununium and Ununtrium. There is even an isotope for an atom with an atomic number of 0! On the other hand, some elements, like Lead, have over 40 different isotopes, each one with a different half life, and a different decay mode. Some elements, like Roentgenium have only one isotope. To better understand what an isotope is in the first place, it can simply be said that an isotope of an element has the same chemical properties, the only difference being its weight and its radioactivity.

More information on how the isotopes decay: Each one of the elements decays in a way that is an attempt to change to a more stable isotopic state. They do this by emitting either alpha or beta radition, or some elements even decay by spontaneous fission, which is when the atom divides in half, causing a large explosion. One last method would be gama-radiation, which emits a gama ray, which is a high energy photon or light. In beta radiation, there are three ways that this radition may be emitted. One is by getting rid of an electron, and then converting, somehow, a neutron to a proton. This is called B- decay. Another way beta radition is emitted is by B+ decay. This is when the isotope emits an anti-electron and converts a proton to a neutron. The last one would be to gain an electron, and then converting a proton to a neutron. Each way is an attempt to make the isotope more stable. Some isotopes emit alpha radition, which is just simply emitting an 4He nucleus. The spontaneous fission method is used in only heavy elements, like Uranium, which is used to make nuclear bombs. As a branch on isotopes, there are sometimes different isomers, which are really just the same isotope, but with a different half life. That simply just means that it decays at a different rate.

__Follow-up Questions__:
What isotopes are most common? Are they used for any scientific purposes? Where are they found and how do they come about?

__Sources__:
http://ie.lbl.gov/education/isotopes.htm