Iron-56
Encyclopedia
Iron-56 is the most common isotope
of iron
. About 91.754% of all iron is iron-56.
Of all isotopes, iron-56 has the lowest mass per nucleon
. With 8.8 MeV
binding energy per nucleon, iron-56 is one of the most tightly bound nuclei.
Nickel-62
has a higher binding energy per nucleon; this is consistent with having a higher mass per nucleon because nickel-62 has a greater proportion of neutron
s; which are slightly more massive than proton
s.
Thus, light elements undergoing nuclear fusion
and heavy elements undergoing nuclear fission
release energy as their nucleons bind more tightly, and the resulting nuclei approach the minimum total energy per nucleon, which occurs at iron-56. As the Universe
ages, more matter is converted into extremely tightly bound nuclei, such as iron-56. This progression of matter towards iron and nickel is one of the phenomena responsible for the heat death of the universe
.
Production of these elements has decreased considerably from what it was at the beginning of the stelliferous era; however, in all likelihood, not all matter will be converted into such elements.
Isotope
Isotopes are variants of atoms of a particular chemical element, which have differing numbers of neutrons. Atoms of a particular element by definition must contain the same number of protons but may have a distinct number of neutrons which differs from atom to atom, without changing the designation...
of iron
Iron
Iron is a chemical element with the symbol Fe and atomic number 26. It is a metal in the first transition series. It is the most common element forming the planet Earth as a whole, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust...
. About 91.754% of all iron is iron-56.
Of all isotopes, iron-56 has the lowest mass per nucleon
Nucleon
In physics, a nucleon is a collective name for two particles: the neutron and the proton. These are the two constituents of the atomic nucleus. Until the 1960s, the nucleons were thought to be elementary particles...
. With 8.8 MeV
Electronvolt
In physics, the electron volt is a unit of energy equal to approximately joule . By definition, it is equal to the amount of kinetic energy gained by a single unbound electron when it accelerates through an electric potential difference of one volt...
binding energy per nucleon, iron-56 is one of the most tightly bound nuclei.
Nickel-62
Nickel-62
Nickel-62 is an isotope of nickel having 28 protons and 34 neutrons.It is a stable isotope, with the highest binding energy per nucleon of any known nuclide . It is often stated that 56Fe is the "most stable nucleus", but actually 56Fe has the lowest mass per nucleon of all nuclides...
has a higher binding energy per nucleon; this is consistent with having a higher mass per nucleon because nickel-62 has a greater proportion of neutron
Neutron
The neutron is a subatomic hadron particle which has the symbol or , no net electric charge and a mass slightly larger than that of a proton. With the exception of hydrogen, nuclei of atoms consist of protons and neutrons, which are therefore collectively referred to as nucleons. The number of...
s; which are slightly more massive than proton
Proton
The proton is a subatomic particle with the symbol or and a positive electric charge of 1 elementary charge. One or more protons are present in the nucleus of each atom, along with neutrons. The number of protons in each atom is its atomic number....
s.
Thus, light elements undergoing nuclear fusion
Nuclear fusion
Nuclear fusion is the process by which two or more atomic nuclei join together, or "fuse", to form a single heavier nucleus. This is usually accompanied by the release or absorption of large quantities of energy...
and heavy elements undergoing nuclear fission
Nuclear fission
In nuclear physics and nuclear chemistry, nuclear fission is a nuclear reaction in which the nucleus of an atom splits into smaller parts , often producing free neutrons and photons , and releasing a tremendous amount of energy...
release energy as their nucleons bind more tightly, and the resulting nuclei approach the minimum total energy per nucleon, which occurs at iron-56. As the Universe
Universe
The Universe is commonly defined as the totality of everything that exists, including all matter and energy, the planets, stars, galaxies, and the contents of intergalactic space. Definitions and usage vary and similar terms include the cosmos, the world and nature...
ages, more matter is converted into extremely tightly bound nuclei, such as iron-56. This progression of matter towards iron and nickel is one of the phenomena responsible for the heat death of the universe
Heat death of the universe
The heat death of the universe is a suggested ultimate fate of the universe, in which the universe has diminished to a state of no thermodynamic free energy and therefore can no longer sustain motion or life. Heat death does not imply any particular absolute temperature; it only requires that...
.
Production of these elements has decreased considerably from what it was at the beginning of the stelliferous era; however, in all likelihood, not all matter will be converted into such elements.