Two examples are: carbon-14 and cobalt-60.
2
There are a lot more than 2 radio active isotopes... To answer this question a naturally or created radioactive element needs to be mentioned.
Carbon dating and tracking.
Chromium has 25 known isotopes, 2 isomers, 3 of which are non-radioactive.
No radioactive isotopes of fluorine are ordinarily found in nature. All elements have radioactive synthetic isotopes, however.
It is not yet discovered since all of the uranium isotopes are having half life for several millions of years. We would be able to find it after atleast 700 millions of years.
C-14 has 2 extra neutrons and is radioactive with a half life of about 5000 years, making it very useful for dating biological material.
All or almost all elements have radioactive isotopes if artificial isotopes are included. Among the naturally occurring elements, uranium, polonium, radium, and thorium have naturally occurring radioactive isotopes on earth.
Sodium does not have naturally occurring radioactive isotopes - as it has only 1 naturally occurring isotope, which has 11 protons and 12 neutrons, and is not radioactive. However, the 18 other known types of sodium isotopes are all radioactive, and sodium-22 (the most stable radioactive sodium isotope) has a half life of 2.6 years.
Both are extremely radioactive isotopes. Gold 186 has 2 more neutrons.
1. All the radioactive isotopes are unstable ! 2. Yes, it is true, the parent isotope (radioactive and unstable) decay and form daughter products.
1. Sodium has 20 isotopes and 2 isomers. 2. Only the isotope 23Na is stable. 3. The stable isotope 23Na and the radioactive isotopes 22Na and 24Na (these isotopes exist in traces) are natural isotopes.