What is the least radioactive isotope?
That would be francium, element 87, whose longest-lived isotope, francium-223, has a half-life of 22 minutes, decaying either into radium by beta decay or astatine by alpha emission.
What are the 3 radioactive isotopes?
Radioactive isotopes of radium, thorium, and uranium, for example, are found naturally in rocks and soil. Uranium and thorium also occur in trace amounts in water. Radon, generated by the radioactive decay of radium, is present in air.
What are 4 radioactive isotopes?
Radioactive Elements
| Element | Most Stable Isotope | Half-life of Most Stable Isotope |
|---|---|---|
| Actinium | Ac-227 | 21.77 years |
| Thorium | Th-229 | 7.54 x 104 years |
| Protactinium | Pa-231 | 3.28 x 104 years |
| Uranium | U-236 | 2.34 x 107 years |
What are some common radioactive isotopes?
What are some commonly-used radioisotopes?
| Radioisotope | Half-life |
|---|---|
| Hydrogen-3 (tritium) | 12.32 years |
| Carbon-14 | 5,700 years |
| Chlorine-36 | 301,000 years |
| Lead-210 | 22.2 years |
What are the least radioactive elements?
Isotopes. Technetium, with atomic number Z = 43, is the lowest-numbered element in the periodic table for which all isotopes are radioactive. The second-lightest exclusively radioactive element, promethium, has atomic number 61.
Why are some isotopes radioactive?
Radioactive isotopes decay spontaneously because their nuclei are unstable. According to the theory, If the ratio of neutrons to protons more than one, or becomes too large, the isotope is radioactive or the atomic number is above 83, the isotope will be radioactive.
Which of the following is not radioactive element?
The correct answer is Cadmium. Cadmium is not a radioactive element.
Are isotopes unstable?
Atoms of the same element with different numbers of neutrons are called isotopes. Many elements have one or more isotopes that are radioactive. These isotopes are called radioisotopes. Their nuclei are unstable, so they break down, or decay, and emit radiation.
What is the rarest non radioactive element?
Astatine is a chemical element with the symbol At and atomic number 85. It is the rarest naturally occurring element in the Earth’s crust, occurring only as the decay product of various heavier elements.
Are all unstable isotopes radioactive?
These isotopes are called radioisotopes. An example of a radioisotope is carbon-14. The nuclei of radioisotopes are unstable, so they constantly decay and emit radiation. In elements with more than 83 protons, all of the isotopes are radioactive.