Melting point The temperature at which the solid—liquid phase change occurs. Boiling point The temperature at which the liquid—gas phase change occurs. Sublimation The transition of a substance directly from the solid to the gas phase without passing through a liquid phase.
Relative atomic mass The mass of an atom relative to that of carbon This is approximately the sum of the number of protons and neutrons in the nucleus. Where more than one isotope exists, the value given is the abundance weighted average. Isotopes Atoms of the same element with different numbers of neutrons. CAS number The Chemical Abstracts Service registry number is a unique identifier of a particular chemical, designed to prevent confusion arising from different languages and naming systems.
Murray Robertson is the artist behind the images which make up Visual Elements. This is where the artist explains his interpretation of the element and the science behind the picture.
Where the element is most commonly found in nature, and how it is sourced commercially. Atomic radius, non-bonded Half of the distance between two unbonded atoms of the same element when the electrostatic forces are balanced. These values were determined using several different methods.
Covalent radius Half of the distance between two atoms within a single covalent bond. Values are given for typical oxidation number and coordination. Electron affinity The energy released when an electron is added to the neutral atom and a negative ion is formed. Electronegativity Pauling scale The tendency of an atom to attract electrons towards itself, expressed on a relative scale. First ionisation energy The minimum energy required to remove an electron from a neutral atom in its ground state.
The oxidation state of an atom is a measure of the degree of oxidation of an atom. It is defined as being the charge that an atom would have if all bonds were ionic. Uncombined elements have an oxidation state of 0. The sum of the oxidation states within a compound or ion must equal the overall charge. Data for this section been provided by the British Geological Survey. An integrated supply risk index from 1 very low risk to 10 very high risk.
This is calculated by combining the scores for crustal abundance, reserve distribution, production concentration, substitutability, recycling rate and political stability scores. The percentage of a commodity which is recycled. A higher recycling rate may reduce risk to supply. The availability of suitable substitutes for a given commodity. The percentage of an element produced in the top producing country.
The higher the value, the larger risk there is to supply. The percentage of the world reserves located in the country with the largest reserves.
A percentile rank for the political stability of the top producing country, derived from World Bank governance indicators. A percentile rank for the political stability of the country with the largest reserves, derived from World Bank governance indicators.
Specific heat capacity is the amount of energy needed to change the temperature of a kilogram of a substance by 1 K. A measure of the stiffness of a substance. It provides a measure of how difficult it is to extend a material, with a value given by the ratio of tensile strength to tensile strain.
A measure of how difficult it is to deform a material. It is given by the ratio of the shear stress to the shear strain. A measure of how difficult it is to compress a substance. It is given by the ratio of the pressure on a body to the fractional decrease in volume. A measure of the propensity of a substance to evaporate.
It is defined as the equilibrium pressure exerted by the gas produced above a substance in a closed system. This Site has been carefully prepared for your visit, and we ask you to honour and agree to the following terms and conditions when using this Site.
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Vaping Study Guide 3 cards. Propylene Glycol. Q: What family does plutonium belongs to? Write your answer Related questions. The element plutonium belongs to what family? What family does plutonium belong to?
Because thorium is a weak alpha emitter, it is relatively safe to use in some commercial applications. Thorium is used as an alloying agent for some metals, such as magnesium, to improve their high-temperature strength. It is also used in elecronic photosensors to measure ultraviolet light. Thorium IV oxide, ThO 2 , used to be used in mantles in portable gas lights.
It is an ingredient in some high-quality lenses, since it forms glasses with a high refractive index and low dispersion. It is also used as a catalyst for the conversion of ammonia to nitric acid, in petroleum cracking, and in the production of sulfuric acid.
Thorium can be converted into thorium by bombardment with neutrons, thereupon decaying into protactinium and then into uranium Uranium undergoes nuclear fission in a chain reaction, and this cycle has potential to be used in nuclear fusion plants.
Because thorium is more abundant than uranium, this may hold some promise in later generations of nuclear power plants. Protactinium is a silvery-white, radioactive metal. Its name is derived from the Greek word proto and actinium , meaning "parent of actinium," because it undergoes radioactive decay to produce actinium. It is found in the Earth's crust in trace amounts, and is among the ten least abundant elements.
It is found in uranium ores such as pitchblende, at very low concentrations. Protactinium is extremely radioactive. It oxidizes slowly in air. There are two naturally occurring isotopes of protactinium: protactinium, with a a half-life of 6 hours and 42 minutes, and protactinium, with a half-life of 32, years.
Because it is highly radioactive and toxic, there are no commercial applications for protactinium. Uranium is a lustrous, silvery-white, hard, dense, malleable, radioactive metal. It is named for the planet Uranus, which had been discovered a few years before the discovery of the element in The planet Uranus had in turn been named for the Greek god of the sky.
It is found in the Earth's crust at a concentration of 2 ppm, making it the 48th most abundant element. Lignite coal and monazite ore also contains trace amounts of uranium. Uranium tarnishes in air to produce an oxide coating. One of the most important properties of uranium was not discovered until , when Henri Becquerel discovered that uranium is radioactive. In one of the classic examples of "accidental" discovery in science, he placed a sample of uranium salts next to a photographic plate, intending to examine the phosphorescence of uranium when exposed to sunlight.
However, he discovered that the plates were exposed, even though the sample had remained in the dark, and realized that the uranium was spontaneously emitting a type of radiation that was not connected to any external stimulation.
There are three major naturally occurring isotopes of uranium there are quite a few other isotopes, but their half-lives are relatively short, and they are not found in any significant amounts in natural sources. The major isotope is uranium, which has an abundance of It emits alpha particles and gamma rays, and is non-fissionable, absorbing neutrons instead of splitting.
Uranium, which has an abundance of 0. It also emits alpha particles and gamma rays, and is fissionable , splitting into lighter atoms when struck by a neutron.
Uranium, which has a half-life of , years, is found at very low concentrations, about 0. Uranium eventually decays into lead, and uranium into lead The radioactive decay of uranium isotopes contributes a great deal to the internal heat of the Earth.
The relative amounts of uranium and lead in rocks can be used in radioactive dating techniques. When neutrons are fired at uranium, the extremely unstable uranium isotope is produced, which quickly splits into two smaller nuclei such as barium and krypton , releasing some of the nuclear binding energy and more neutrons.
This process is known as nuclear fission. These neutrons can collide with other uranium isotopes, causing them to split and release energy and even more neutrons in a chain reaction. Moderators such as beryllium, graphite, water, or heavy water D 2 O slow down the neutrons that are released in fission reactions, producing "thermal neutrons" that can be captured by uranium atoms, rather than simply bouncing off.
In "light water" reactors, the moderator is ordinary water — i. In "heavy water" reactors, the moderator is D 2 O — i. Since plutonium is the first in a string of plutonium isotopes created from uranium in a reactor, the longer a sample of uranium is irradiated, the greater the percentage of heavier isotopes.
Plutonium must be chemically separated from the fission products and remaining uranium in the irradiated reactor fuel. This chemical separation is called reprocessing. It is important to remember that this classification of plutonium according to grades is somewhat arbitrary. The ability of countries to build nuclear arsenals from reactor grade plutonium is not just a theoretical construct. It is a proven fact. All grades of plutonium can be used as weapons of radiological warfare which involve weapons that disperse radioactivity without a nuclear explosion.
Posted on July, Last modified April, Download this page as a PDF. Table 1. C Boiling point: deg. Table 2. Chemical properties and hazards of plutonium. Table 3. Humid, elevated temperatures PuO2 readily reacts to form plutonium dioxide Important Plutonium Compounds and their Uses Plutonium combines with oxygen, carbon, and fluorine to form compounds which are used in the nuclear industry, either directly or as intermediates.
Table 4. Formation and Grades of Plutonium Plutonium is formed in both civilian and military reactors from uranium Table 5. Cochran, Thomas B.
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