A report on Isotope and Chemical element

The three naturally-occurring isotopes of hydrogen. The fact that each isotope has one proton makes them all variants of hydrogen: the identity of the isotope is given by the number of protons and neutrons. From left to right, the isotopes are protium (1H) with zero neutrons, deuterium (2H) with one neutron, and tritium (3H) with two neutrons.

The chemical elements ordered in the periodic table

In the bottom right corner of J. J. Thomson's photographic plate are the separate impact marks for the two isotopes of neon: neon-20 and neon-22.

$Estimated distribution of dark matter and dark energy in the universe. Only the fraction of the mass and energy in the universe labeled "atoms" is composed of chemical elements.$

Periodic table showing the cosmogenic origin of each element in the Big Bang, or in large or small stars. Small stars can produce certain elements up to sulfur, by the alpha process. Supernovae are needed to produce "heavy" elements (those beyond iron and nickel) rapidly by neutron buildup, in the r-process. Certain large stars slowly produce other elements heavier than iron, in the s-process; these may then be blown into space in the off-gassing of planetary nebulae

Abundances of the chemical elements in the Solar System. Hydrogen and helium are most common, from the Big Bang. The next three elements (Li, Be, B) are rare because they are poorly synthesized in the Big Bang and also in stars. The two general trends in the remaining stellar-produced elements are: (1) an alternation of abundance in elements as they have even or odd atomic numbers (the Oddo-Harkins rule), and (2) a general decrease in abundance as elements become heavier. Iron is especially common because it represents the minimum energy nuclide that can be made by fusion of helium in supernovae.

Mendeleev's 1869 periodic table: An experiment on a system of elements. Based on their atomic weights and chemical similarities.

Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numbers) due to different numbers of neutrons in their nuclei.

- Isotope

Carbon atoms may have different numbers of neutrons; atoms of the same element having different numbers of neutrons are known as isotopes of the element.

- Chemical element

32 related topics with Alpha

Periodic table

11 links

3D views of some hydrogen-like atomic orbitals showing probability density and phase (g orbitals and higher are not shown)

Idealized order of shell-filling (most accurate for n  ≲ 4.)

Graph of first ionisation energies of the elements in electronvolts (predictions used for elements 105–118)

Flowing liquid mercury. Its liquid state at room temperature is a result of special relativity.

A periodic table colour-coded to show some commonly used sets of similar elements. The categories and their boundaries differ somewhat between sources. Alkali metals
Alkaline earth metals
Lanthanides
Actinides
Transition metals Other metals
Metalloids
Other nonmetals
Halogens
Noble gases

One possible form of the extended periodic table to element 172, suggested by Finnish chemist Pekka Pyykkö. Deviations from the Madelung order (8s < < 6f < 7d < 8p) begin to appear at elements 139 and 140, though for the most part it continues to hold approximately.

Otto Theodor Benfey's spiral periodic table (1964)

Arsenic, an element often called a semi-metal or metalloid

The periodic table, also known as the periodic table of the (chemical) elements, is a tabular display of the chemical elements.

Atoms with the same number of protons but different numbers of neutrons are called isotopes of the same chemical element.

Uranium

11 links

Various militaries use depleted uranium as high-density penetrators.

The most visible civilian use of uranium is as the thermal power source used in nuclear power plants.

Uranium ceramic glaze glowing under UV light Design and developed by Dr. Sencer Sarı

Uranium glass used as lead-in seals in a vacuum capacitor

The planet Uranus, which uranium is named after

Antoine Henri Becquerel discovered the phenomenon of radioactivity by exposing a photographic plate to uranium in 1896.

Cubes and cuboids of uranium produced during the Manhattan project

The mushroom cloud over Hiroshima after the dropping of the uranium-based atomic bomb nicknamed 'Little Boy'

Four light bulbs lit with electricity generated from the first artificial electricity-producing nuclear reactor, EBR-I (1951)

U.S. and USSR/Russian nuclear weapons stockpiles, 1945–2005

Uraninite, also known as pitchblende, is the most common ore mined to extract uranium.

The evolution of Earth's radiogenic heat flow over time: contribution from 235U in red and from 238U in green

Citrobacter species can have concentrations of uranium in their cells 300 times the level of the surrounding environment.

Monthly uranium spot price in US$ per pound. The 2007 price peak is clearly visible.

Uranium in its oxidation states III, IV, V, VI

Uranium hexafluoride is the feedstock used to separate uranium-235 from natural uranium.

Cascades of gas centrifuges are used to enrich uranium ore to concentrate its fissionable isotopes.

World uranium production (mines) and demand<ref name="WNA-WUM" />

alt=A yellow sand-like rhombic mass on black background.|Yellowcake is a concentrated mixture of uranium oxides that is further refined to extract pure uranium.

Uranium is a chemical element with the symbol U and atomic number 92.

Uranium-235 is the only naturally occurring fissile isotope, which makes it widely used in nuclear power plants and nuclear weapons.

Neutron

10 links

Subatomic particle, symbol or, which has a neutral charge, and a mass slightly greater than that of a proton.

Nuclear fission caused by absorption of a neutron by uranium-235. The heavy nuclide fragments into lighter components and additional neutrons.

Models depicting the nucleus and electron energy levels in hydrogen, helium, lithium, and neon atoms. In reality, the diameter of the nucleus is about 100,000 times smaller than the diameter of the atom.

A schematic of the nucleus of an atom indicating radiation, the emission of a fast electron from the nucleus (the accompanying antineutrino is omitted). In the Rutherford model for the nucleus, red spheres were protons with positive charge and blue spheres were protons tightly bound to an electron with no net charge.
The inset shows beta decay of a free neutron as it is understood today; an electron and antineutrino are created in this process.

The Feynman diagram for beta decay of a neutron into a proton, electron, and electron antineutrino via an intermediate heavy W boson

The leading-order Feynman diagram for decay of a proton into a neutron, positron, and electron neutrino via an intermediate boson.

Institut Laue–Langevin (ILL) in Grenoble, France – a major neutron research facility.

Cold neutron source providing neutrons at about the temperature of liquid hydrogen

The fusion reaction rate increases rapidly with temperature until it maximizes and then gradually drops off. The D–T rate peaks at a lower temperature (about 70 keV, or 800 million kelvins) and at a higher value than other reactions commonly considered for fusion energy.

Transmutation flow in light water reactor, which is a thermal-spectrum reactor

Atoms of a chemical element that differ only in neutron number are called isotopes.

Radioactive decay

9 links

Process by which an unstable atomic nucleus loses energy by radiation.

Pierre and Marie Curie in their Paris laboratory, before 1907

Taking an X-ray image with early Crookes tube apparatus in 1896. The Crookes tube is visible in the centre. The standing man is viewing his hand with a fluoroscope screen; this was a common way of setting up the tube. No precautions against radiation exposure are being taken; its hazards were not known at the time.

Graphic showing relationships between radioactivity and detected ionizing radiation

Alpha particles may be completely stopped by a sheet of paper, beta particles by aluminium shielding. Gamma rays can only be reduced by much more substantial mass, such as a very thick layer of lead.

137Cs decay scheme showing half-lives, daughter nuclides, and types and proportion of radiation emitted

Transition diagram for decay modes of a radionuclide, with neutron number N and atomic number Z (shown are α, β±, p+, and n0 emissions, EC denotes electron capture).

Types of radioactive decay related to neutron and proton numbers

Simulation of many identical atoms undergoing radioactive decay, starting with either 4 atoms (left) or 400 (right). The number at the top indicates how many half-lives have elapsed.

Example of diurnal and seasonal variations in gamma ray detector response.

Gamma-ray energy spectrum of uranium ore (inset). Gamma-rays are emitted by decaying nuclides, and the gamma-ray energy can be used to characterize the decay (which nuclide is decaying to which). Here, using the gamma-ray spectrum, several nuclides that are typical of the decay chain of 238U have been identified: 226Ra, 214Pb, 214Bi.

The trefoil symbol used to warn of presence of radioactive material or ionising radiation

2007 ISO radioactivity hazard symbol intended for IAEA Category 1, 2 and 3 sources defined as dangerous sources capable of death or serious injury<ref>IAEA news release Feb 2007</ref>

The dangerous goods transport classification sign for radioactive materials

When the number of protons changes, an atom of a different chemical element is created.

In neutron emission, extremely neutron-rich nuclei, formed due to other types of decay or after many successive neutron captures, occasionally lose energy by way of neutron emission, resulting in a change from one isotope to another of the same element.

Decay chain of 238U, the primordial progenitor of 226Ra

Radium

7 links

Marie and Pierre Curie experimenting with radium, a drawing by André Castaigne

Glass tube of radium chloride kept by the US Bureau of Standards that served as the primary standard of radioactivity for the United States in 1927.

Self-luminous white paint which contains radium on the face and hand of an old clock.

Radium watch hands under ultraviolet light

Hotel postcard advertising radium baths, c.1940s

Ad for Radior cosmetics which the manufacturer claimed contained radium, that was supposed to have health benefits for one's skin. Powders, skin creams and soap were part of this line.

Monument to the Discovery of Radium in Jáchymov

Radium is a chemical element with the symbol Ra and atomic number 88.

All isotopes of radium are highly radioactive, with the most stable isotope being radium-226, which has a half-life of 1600 years and decays into radon gas (specifically the isotope radon-222).

Relative abundance of the chemical elements in the Earth's upper continental crust, on a per-atom basis

Primordial nuclide

7 links

Formed.

These 34 primordial radionuclides represent isotopes of 28 separate elements.

Proton

6 links

Stable subatomic particle, symbol, H+, or 1H+ with a positive electric charge of +1e elementary charge.

Ernest Rutherford at the first Solvay Conference, 1911

Proton detected in an isopropanol cloud chamber

Protium, the most common isotope of hydrogen, consists of one proton and one electron (it has no neutrons). The term "hydrogen ion" implies that that H-atom has lost its one electron, causing only a proton to remain. Thus, in chemistry, the terms "proton" and "hydrogen ion" (for the protium isotope) are used synonymously

Since each element has a unique number of protons, each element has its own unique atomic number, which determines the number of atomic electrons and consequently the chemical characteristics of the element.

The nucleus of the most common isotope of the hydrogen atom (with the chemical symbol "H") is a lone proton.

Periodisches System der Elemente (1904–1945, now at the Gdańsk University of Technology): lack of elements: 84 polonium Po (though discovered as early as in 1898 by Maria Sklodowska-Curie), 85 astatine At (1940, in Berkeley), 87 francium Fr (1939, in France), 93 neptunium Np (1940, in Berkeley) and other actinides and lanthanides. Old symbols for: 18 argon Ar (here: A), 43 technetium Tc (Ma, masurium), 54 xenon Xe (X), 86 radon, Rn (Em, emanation)

Technetium

6 links

Pertechnetate is one of the most available forms of technetium. It is structurally related to permanganate.

TcCl4 forms chain-like structures, similar to the behavior of several other metal tetrachlorides.

Chloro-containing coordination complexes of technetium (Tc-99) in various oxidation states: Tc(III), Tc(IV), Tc(V), and Tc(VI) represented.

Technetium (99mTc) sestamibi ("Cardiolite") is widely used for imaging of the heart.

The first technetium-99m generator, unshielded, 1958. A Tc-99m pertechnetate solution is being eluted from Mo-99 molybdate bound to a chromatographic substrate

Technetium scintigraphy of a neck of Graves' disease patient

Technetium is a chemical element with the symbol Tc and atomic number 43.

In 1937, they succeeded in isolating the isotopes technetium-95m and technetium-97.

Atomic nucleus

5 links

Small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment.

A figurative depiction of the helium-4 atom with the electron cloud in shades of gray. In the nucleus, the two protons and two neutrons are depicted in red and blue. This depiction shows the particles as separate, whereas in an actual helium atom, the protons are superimposed in space and most likely found at the very center of the nucleus, and the same is true of the two neutrons. Thus, all four particles are most likely found in exactly the same space, at the central point. Classical images of separate particles fail to model known charge distributions in very small nuclei. A more accurate image is that the spatial distribution of nucleons in a helium nucleus is much closer to the helium electron cloud shown here, although on a far smaller scale, than to the fanciful nucleus image. Both the helium atom and its nucleus are spherically symmetric.

Which chemical element an atom represents is determined by the number of protons in the nucleus; the neutral atom will have an equal number of electrons orbiting that nucleus.

Neutrons can explain the phenomenon of isotopes (same atomic number with different atomic mass).

Periodic table showing the currently believed origins of each element. Elements from carbon up to sulfur may be made in stars of all masses by charged-particle fusion reactions. Iron group elements originate mostly from the nuclear-statistical equilibrium process in thermonuclear supernova explosions. Elements beyond iron are made in high-mass stars with slow neutron capture (s-process), and by rapid neutron capture in the r-process, with origins being debated among rare supernova variants and compact-star collisions. Note that this graphic is a first-order simplification of an active research field with many open questions.

Nucleosynthesis

6 links

Process that creates new atomic nuclei from pre-existing nucleons and nuclei.

Abundances of the chemical elements in the Solar System. Hydrogen and helium are most common, residuals within the paradigm of the Big Bang. The next three elements (Li, Be, B) are rare because they are poorly synthesized in the Big Bang and also in stars. The two general trends in the remaining stellar-produced elements are: (1) an alternation of abundance of elements according to whether they have even or odd atomic numbers, and (2) a general decrease in abundance, as elements become heavier. Within this trend is a peak at abundances of iron and nickel, which is especially visible on a logarithmic graph spanning fewer powers of ten, say between logA=2 (A=100) and logA=6 (A=1,000,000).

The rest is traces of other elements such as lithium and the hydrogen isotope deuterium.

The first ideas on nucleosynthesis were simply that the chemical elements were created at the beginning of the universe, but no rational physical scenario for this could be identified.