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Atoms found in nature are either stable or unstable. An atom is stable if the forces among the particles that makeup the nucleus are balanced. An atom is unstable (radioactive) if these forces are unbalanced; if the nucleus has an excess of internal energy.
Radioisotopes are unstable isotopes of chemical elements that undergo radioactive decay. Stable isotopes are very stable and do not undergo radioactive decay.
Nuclear Stability is a concept that helps to identify the stability of an isotope. The two main factors that determine nuclear stability are the neutron/proton ratio and the total number of nucleons in the nucleus.
Isotope Facts There are two main types of isotopes: stable and unstable (radioactive). There are 254 known stable isotopes. All artificial (lab-made) isotopes are unstable and therefore radioactive; scientists call them radioisotopes. Some elements can only exist in an unstable form (for example, uranium).
Carbon-12, with six protons and six neutrons, is a stable nucleus, meaning that it does not spontaneously emit radioactivity. Carbon-14, with six protons and eight neutrons, is unstable and naturally radioactive.
Stability of Isotopes. Atoms need a certain ratio of neutrons to protons to have a stable nucleus. Having too many or too few neutrons relative to protons results in an unstable, or radioactive, nucleus that will sooner or later break down to a more stable form.
Stable isotopes do not decay into other elements. In contrast, radioactive isotopes (e.g., 14C) are unstable and will decay into other elements.
The neutron/proton ratio and the total number of nucleons determine isotope stability. The principal factor is the neutron to proton ratio. At close distances, a strong nuclear force exists between nucleons. This attractive force comes from the neutrons.
Commonly analysed stable isotopes include oxygen, carbon, nitrogen, hydrogen and sulfur. These isotope systems have been under investigation for many years in order to study processes of isotope fractionation in natural systems because they are relatively simple to measure.
| Z | Element | unstable in italics odd neutron number in pink |
|---|---|---|
| 52 | tellurium | 124 Te |
| 44 | ruthenium | 100 Ru |
| 66 | dysprosium | 160 Dy |
| 70 | ytterbium | 176 Yb |
Stable isotopes can be used by measuring their amounts and proportions in samples, for example in water samples. Naturally-occurring stable isotopes of water and other substances are used to trace the origin, history, sources, sinks and interactions in water, carbon and nitrogen cycles.
| Element Atomic Number | Element Symbol | Element Name |
|---|---|---|
| 4 | Be | Beryllium |
| 5 | B | Boron |
| 6 | C | Carbon |
| 7 | N | Nitrogen |
Tin has the most stable isotopes of all the elements. Tin is a metallic element on the periodic table with an atomic number of 50.
Characteristics. Francium is one of the most unstable of the naturally occurring elements: its longest-lived isotope, francium-223, has a half-life of only 22 minutes.
When the atom is stable, it has a net electrical charge of 0, meaning that the number of protons equals the number of electrons. The nucleus is also balanced, in that the number of protons equals the number of neutrons.
The mutation Unstable Isotope is similar to this — it irradiates melee attackers and causes radiation, while also dealing damage to you. However, some enemies are immune to Unstable Isotope’s radiation.
Lead-206 is a stable isotope because it will not decay into a different element (non-stable isotopes will undergo radioactive decay and change into a…
Natural bromine is a mixture of two stable isotopes: bromine-79 (50.54 percent) and bromine-81 (49.46 percent). Of the 17 known radioactive isotopes of the element, bromine-77 has the longest half-life (57 hours).
One oxygen atom is unstable since it has only 6 electrons in the outermost shell. For an atom to be stable it needs 8 electrons. So, for the oxygen atom to be stable it requires two more electrons in the valence shell.
2.2 Nitrogen. Unlike phosphorus, nitrogen occurs most commonly as an extremely stable atmospheric gas, dinitrogen (N2).
Conclusion: The doses of stable isotope tracer substances that are used for clinical diagnostic and research purposes appear safe and without any adverse effects. Stable isotope tracers should only be used in children if the trace is safe at the doses applied, and tracer is chemically pure and stable.
An unstable atom has excess internal energy, with the result that the nucleus can undergo a spontaneous change towards a more stable form. This is called ‘radioactive decay’. … Unstable isotopes (which are thus radioactive) are called radioisotopes. Some elements, eg uranium, have no stable isotopes.
Why some elements are radioactive (unstable). When the atoms of an element have extra neutrons or protons it creates extra energy in the nucleus and causes the atom to become unbalanced or unstable.
Lithium is a relatively unstable element because its stable isotopes have a very low binding energy level. This means they are not prone to fission, which is breaking down. This is why, lithium is less common in the galaxy than some other elements with a higher atomic weight.
The last element in the periodic table that has a stable isotope is lead (Z = 82), with stability (i.e. half-lives of the longest lived isotopes) generally decreasing in heavier elements. … The stability of a nucleus is determined by its binding energy, higher binding energy conferring greater stability.