Einsteinium is the seventh transuranic element, and an actinide. Zirconium is mainly used as a refractory and opacifier, although small amounts are used as an alloying agent for its strong resistance to corrosion. Lead is soft and malleable, and has a relatively low melting point. Mendelevium is a metallic radioactive transuranic element in the actinide series, it is the first element that currently cannot be produced in macroscopic quantities. The chemical symbol for Arsenic is As. The chemical symbol for Chlorine is Cl. To access our product user manuals, follow the links below. Radioactive 60 Co is used in the treatment of cancer. Lead is a heavy metal that is denser than most common materials. The total number of neutrons in the nucleus of an atom is called the neutron number of the atom and is given the symbol N. Neutron number plus atomic number equals atomic mass number: N+Z=A. The chemical symbol for Hafnium is Hf. Bismuth is a brittle metal with a silvery white color when freshly produced, but surface oxidation can give it a pink tinge. Cadmium is a chemical element with atomic number 48 which means there are 48 protons and 48 electrons in the atomic structure. Sulfur is a chemical element with atomic number 16 which means there are 16 protons and 16 electrons in the atomic structure. Since the density (ρ) of a substance is the total mass (m) of that substance divided by the total volume (V) occupied by that substance, it is obvious, the density of a substance strongly depends on its atomic mass and also on the atomic number density (N; atoms/cm3). The chemical symbol for Boron is B. Only about 5×10−8% of all matter in the universe is europium. The chemical symbol for Sodium is Na. The atomic number of Cobalt is 27 with an atomic mass of 58.933195. It is a member of the chalcogen group on the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as well as with other compounds. It is by mass the most common element on Earth, forming much of Earth’s outer and inner core. Silicon is a chemical element with atomic number 14 which means there are 14 protons and 14 electrons in the atomic structure. The chemical symbol for Silicon is Si. The chemical symbol for Krypton is Kr. The Cookies Statement is part of our Privacy Policy. If you continue to use this site we will assume that you are happy with it. Lithium is a chemical element with atomic number 3 which means there are 3 protons and 3 electrons in the atomic structure. If you want to get in touch with us, please do not hesitate to contact us via e-mail: Discoverer: Ramsey, Sir William and Cleve, Per Teodor. It is present in the sun, in soil, and in bodies of plants and animals. Discoverer: McMillan, Edwin M. and Abelson, Philip H. Discoverer: Glenn T. Seaborg, Joseph W. Kennedy, Edward M. McMillan, Arthur C. Wohl, Discoverer: Glenn T. Seaborg, Ralph A. James, Leon O. Morgan, Albert Ghiorso, Discoverer: Glenn T. Seaborg, Ralph A. James, Albert Ghiorso, Discoverer: Stanley G. Thompson, Glenn T. Seaborg, Kenneth Street, Jr., Albert Ghiorso, Discoverer: Stanley G. Thompson, Glenn T. Seaborg, Bernard G. Harvey, Gregory R. Choppin, Albert Ghiorso, Discoverer: Albert Ghiorso, Glenn T. Seaborg, Torbørn Sikkeland, John R. Walton, Discoverer: Albert Ghiorso, Torbjørn Sikkeland, Almon E. Larsh, Robert M. Latimer, Copyright 2020 Periodic Table | All Rights Reserved |. The chemical symbol for Californium is Cf. The atomic mass is the mass of an atom. The chemical symbol for Lead is Pb. Thorium is moderately hard, malleable, and has a high melting point. Chlorine is a yellow-green gas at room temperature. Radon occurs naturally as an intermediate step in the normal radioactive decay chains through which thorium and uranium slowly decay into lead. Its extreme rarity in the Earth’s crust, comparable to that of platinum. The chemical symbol for Gadolinium is Gd. Up to date, curated data provided by Mathematica 's ElementData function from Wolfram Research, Inc. The various species of atoms whose nuclei contain particular numbers of protons and neutrons are called nuclides. Titanium is a lustrous transition metal with a silver color, low density, and high strength. The chemical symbol for Beryllium is Be. Lead is a chemical element with atomic number 82 which means there are 82 protons and 82 electrons in the atomic structure.    Halogens The chemical symbol for Fluorine is F. Fluorine is the lightest halogen and exists as a highly toxic pale yellow diatomic gas at standard conditions. One atomic mass unit is equal to 1.66 x 10-24 grams. Gadolinium is a chemical element with atomic number 64 which means there are 64 protons and 64 electrons in the atomic structure. It is a noble metal and a member of the platinum group. Sources, facts, uses, scarcity (SRI), podcasts, alchemical symbols, videos and images. agreement. The chemical symbol for Actinium is Ac. Polonium is a chemical element with atomic number 84 which means there are 84 protons and 84 electrons in the atomic structure. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins. In nuclear industry, especially artificial xenon 135 has a tremendous impact on the operation of a nuclear reactor. Krypton is a chemical element with atomic number 36 which means there are 36 protons and 36 electrons in the atomic structure. Nuclides that have the same neutron number but a different proton number are called isotones. Cobalt is a naturally-occurring element that has properties similar to those of iron and nickel. Lutetium is the last element in the lanthanide series, and it is traditionally counted among the rare earths. The chemical symbol for Erbium is Er. Platinum is used in catalytic converters, laboratory equipment, electrical contacts and electrodes, platinum resistance thermometers, dentistry equipment, and jewelry. The chemical symbol for Polonium is Po. Cobalt is a chemical element with atomic number 27 which means there are 27 protons and 27 electrons in the atomic structure. Astatine is the rarest naturally occurring element on the Earth’s crust. Zirconium is widely used as a cladding for nuclear reactor fuels. The chemical symbol for Ruthenium is Ru. All of the alkali metals have a single valence electron in the outer electron shell, which is easily removed to create an ion with a positive charge – a cation, which combines with anions to form salts. The chemical symbol for Argon is Ar. cobalt 60: (Co) [ ko´bawlt ] a chemical element, atomic number 27, atomic weight 58.933. Ytterbium is a chemical element with atomic number 70 which means there are 70 protons and 70 electrons in the atomic structure. Indium is a chemical element with atomic number 49 which means there are 49 protons and 49 electrons in the atomic structure. Discoverer: Corson, Dale R. and Mackenzie, K. R. The actinide or actinoid series encompasses the 15 metallic chemical elements with atomic numbers from 89 to 103, actinium through lawrencium. The absorption of a neutron converts cobalt-59 to radioactive cobalt-60 (half-life 5.272 years), which decays by the emission of a beta particle and a high-energy gamma ray to nickel-60.    Other Metals The chemical symbol for Einsteinium is Es. It is even less abundant than the so-called rare earths. Notes on the properties of Cobalt: Specific Heat: Value given for solid phase. Approximately 60–70% of thallium production is used in the electronics industry. Chemically, sulfur reacts with all elements except for gold, platinum, iridium, tellurium, and the noble gases. Argon is a chemical element with atomic number 18 which means there are 18 protons and 18 electrons in the atomic structure. Calcium is a chemical element with atomic number 20 which means there are 20 protons and 20 electrons in the atomic structure. This equilibrium also known as “samarium 149 reservoir”, since all of this promethium must undergo a decay to samarium. The chemical symbol for Nickel is Ni. Lead is widely used as a gamma shield. Discoverer: Marinsky, Jacob A. and Coryell, Charles D. and Glendenin, Lawerence. If we include man made elements, the densest so far is Hassium. It has the symbol Co. Cobalt-60, a radioactive isotope of cobalt, is an important source of gamma rays and is used to treat some forms of cancer and as a medical tracer. Iodine is the least abundant of the stable halogens, being the sixty-first most abundant element. The chemical symbol for Cobalt is Co . Praseodymium is a soft, silvery, malleable and ductile metal, valued for its magnetic, electrical, chemical, and optical properties. Titanium can be used in surface condensers. The chemical symbol for Ytterbium is Yb. Platinum is a chemical element with atomic number 78 which means there are 78 protons and 78 electrons in the atomic structure. The chemical symbol for Tantalum is Ta. The chemical symbol for Cobalt is Co. Cobalt is found in the Earth’s crust only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. It has remarkable resistance to corrosion, even at high temperatures, and is therefore considered a noble metal. The chemical symbol for Neodymium is Nd. Most common minerals of cobalt are cobaltite (cobalt sulfoarsenide mineral), linnaeite (… The chemical symbol for Mendelevium is Md. Arsenic is a chemical element with atomic number 33 which means there are 33 protons and 33 electrons in the atomic structure. In fact their absorption cross-sections are the highest among all stable isotopes. A freshly exposed surface of pure copper has a reddish-orange color. Plutonium is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized.  Help Europium is a moderately hard, silvery metal which readily oxidizes in air and water. Hafnium’s large neutron capture cross-section makes it a good material for neutron absorption in control rods in nuclear power plants, but at the same time requires that it be removed from the neutron-transparent corrosion-resistant zirconium alloys used in nuclear reactors. Fermium is a chemical element with atomic number 100 which means there are 100 protons and 100 electrons in the atomic structure. The chemical symbol for Tellurium is Te. cobalt: (Co) [ ko´bawlt ] a chemical element, atomic number 27, atomic weight 58.933. It is found in … Cobalt, metallic chemical element, one of the transition elements, atomic number 27. Einsteinium is a chemical element with atomic number 99 which means there are 99 protons and 99 electrons in the atomic structure. Carbon is the 15th most abundant element in the Earth’s crust, and the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. These condensers use tubes that are usually made of stainless steel, copper alloys, or titanium depending on several selection criteria (such as thermal conductivity or corrosion resistance). Atomic mass of Cobalt is 58.9332 u.. Copper is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. Atomic Number of Cobalt. Barium is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Francium is a chemical element with atomic number 87 which means there are 87 protons and 87 electrons in the atomic structure. The chemical symbol for Nitrogen is N. Nitrogen is a colourless, odourless unreactive gas that forms about 78% of the earth’s atmosphere. Mass was no longer considered unchangeable in the closed system. Plutonium is a chemical element with atomic number 94 which means there are 94 protons and 94 electrons in the atomic structure. The chemical symbol for Sulfur is S. Sulfur is abundant, multivalent, and nonmetallic. Natural boron consists primarily of two stable isotopes, 11B (80.1%) and 10B (19.9%). The chemical symbol for Oxygen is O. Boron is a chemical element with atomic number 5 which means there are 5 protons and 5 electrons in the atomic structure. The atomic mass or relative isotopic mass refers to the mass of a single particle, and therefore is tied to a certain specific isotope of an element. Lanthanoids comprise the 15 metallic chemical elements with atomic numbers 57 through 71, from lanthanum through lutetium. cobalt 57 a radioisotope of cobalt, atomic mass 57, having a half-life of 270 days; used as a label for cyanocobalamin. Marmite, which we eat here in England and love it or hate it is a source of vitamin B 12, actually a cobalt complex. Californium is an actinide element, the sixth transuranium element to be synthesized, and has the second-highest atomic mass of all the elements that have been produced in amounts large enough to see with the unaided eye (after einsteinium). Osmium is a chemical element with atomic number 76 which means there are 76 protons and 76 electrons in the atomic structure. Sodium is an alkali metal, being in group 1 of the periodic table, because it has a single electron in its outer shell that it readily donates, creating a positively charged atom—the Na+ cation. George Brandt discovered cobalt in 1735. The chemical symbol for Radium is Ra. Potassium is a chemical element with atomic number 19 which means there are 19 protons and 19 electrons in the atomic structure. The chemical symbol for Iron is Fe.  Links, Show Table With: Because of its high chemical reactivity, barium is never found in nature as a free element. Although classified as a rare earth element, samarium is the 40th most abundant element in the Earth’s crust and is more common than such metals as tin. Like all elements with atomic number over 100, nobelium can only be produced in particle accelerators by bombarding lighter elements with charged particles. Its abundance in rocky planets like Earth is due to its abundant production by fusion in high-mass stars. The chemical symbol for Tin is Sn. The chemical symbol for Cerium is Ce. Erbium is a silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements. The chemical symbol for Zinc is Zn. Hafnium is a lustrous, silvery gray, tetravalent transition metal, hafnium chemically resembles zirconium and is found in many zirconium minerals. Molybdenum is a chemical element with atomic number 42 which means there are 42 protons and 42 electrons in the atomic structure. Pure radium is silvery-white alkaline earth metal. Melting point of Cobalt is 1495 °C and its the boiling point is 2870 °C. For example, 63Cu (29 protons and 34 neutrons) has a mass number of 63 and an isotopic mass in its nuclear ground state is 62.91367 u. The chemical symbol for Holmium is Ho. The name samarium is after the mineral samarskite from which it was isolated. The difference is a measure of the nuclear binding energy which holds the nucleus together. Antimony compounds have been known since ancient times and were powdered for use as medicine and cosmetics, often known by the Arabic name, kohl. The size and mass of atoms are so small that the use of normal measuring units, while possible, is often inconvenient. Nickel is a silvery-white lustrous metal with a slight golden tinge. The chemical symbol for Calcium is Ca. Atomic Mass Number – Does it conserve in a nuclear reaction?    Electron Configuration The most commonly used spontaneous fission neutron source is the radioactive isotope californium-252. Cerium is the second element in the lanthanide series. Hydrogen is a chemical element with atomic number 1 which means there are 1 protons and 1 electrons in the atomic structure. Element Cobalt (Co), Group 9, Atomic Number 27, d-block, Mass 58.933. Tungsten is a chemical element with atomic number 74 which means there are 74 protons and 74 electrons in the atomic structure. The chemical symbol for Germanium is Ge. Germanium is a chemical element with atomic number 32 which means there are 32 protons and 32 electrons in the atomic structure. Polonium is a rare and highly radioactive metal with no stable isotopes, polonium is chemically similar to selenium and tellurium, though its metallic character resembles that of its horizontal neighbors in the periodic table: thallium, lead, and bismuth. (See Appendix 6.) Silicon is a hard and brittle crystalline solid with a blue-grey metallic lustre, it is a tetravalent metalloid and semiconductor. Yttrium is a chemical element with atomic number 39 which means there are 39 protons and 39 electrons in the atomic structure. Members are cobalt (Co), rhodium (Rh), iridium (Ir) and meitnerium (Mt). Chemically, indium is similar to gallium and thallium. Actinium is a chemical element with atomic number 89 which means there are 89 protons and 89 electrons in the atomic structure. Fluorine is a chemical element with atomic number 9 which means there are 9 protons and 9 electrons in the atomic structure. Rubidium is a chemical element with atomic number 37 which means there are 37 protons and 37 electrons in the atomic structure. Rhenium is a silvery-white, heavy, third-row transition metal in group 7 of the periodic table. Sodium is a soft, silvery-white, highly reactive metal. Actinium gave the name to the actinide series, a group of 15 similar elements between actinium and lawrencium in the periodic table. Tellurium is chemically related to selenium and sulfur. Atomic Number of Cobalt is 27.. Chemical symbol for Cobalt is Co. For example, the neutron number of uranium-238 is 238-92=146. The chemical symbol for Indium is In. Aluminium is a silvery-white, soft, nonmagnetic, ductile metal in the boron group. The chemical symbol for Americium is Am. Discoverer: Scientists at Dubna, Russia (1964)/Albert Ghiorso et. A colorless, odorless, tasteless noble gas, krypton occurs in trace amounts in the atmosphere and is often used with other rare gases in fluorescent lamps. Copyright © 1996-2012 Yinon Bentor. Antimony is a chemical element with atomic number 51 which means there are 51 protons and 51 electrons in the atomic structure. Neutron number is rarely written explicitly in nuclide symbol notation, but appears as a subscript to the right of the element symbol. Lutetium is a chemical element with atomic number 71 which means there are 71 protons and 71 electrons in the atomic structure. Zirconium is a lustrous, grey-white, strong transition metal that resembles hafnium and, to a lesser extent, titanium. Naturally occurring potassium is composed of three isotopes, of which 40K is radioactive. Gallium is a chemical element with atomic number 31 which means there are 31 protons and 31 electrons in the atomic structure. These have similar chemical properties, but palladium has the lowest melting point and is the least dense of them. Atomic structure of Cobalt includes atomic number, atomic weight, electron configuration Cadmium is a soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Despite its high price and rarity, thulium is used as the radiation source in portable X-ray devices. Cobalt is a chemical element with atomic number 27 and symbol Co. Know the Uses of Cobalt, Atomic Mass of Cobalt, Chemical Properties of Cobalt & more at BYJU'S. Dysprosium is used for its high thermal neutron absorption cross-section in making control rods in nuclear reactors, for its high magnetic susceptibility in data storage applications. A major development was the discovery that steel could be made highly resistant to corrosion and discoloration by adding metallic chromium to form stainless steel. and Gay-Lussac, L.-J. The chemical symbol for Antimony is Sb. Bismuth is a pentavalent post-transition metal and one of the pnictogens, chemically resembles its lighter homologs arsenic and antimony. Uranium is a chemical element with atomic number 92 which means there are 92 protons and 92 electrons in the atomic structure. Ruthenium is a rare transition metal belonging to the platinum group of the periodic table. Thallium is a soft gray post-transition metal is not found free in nature. Under normal conditions, sulfur atoms form cyclic octatomic molecules with a chemical formula S8. It has an atomic number of 27. Cobalt is a chemical element with atomic number 27 which means there are 27 protons and 27 electrons in the atomic structure.The chemical symbol for Cobalt is Co. Atomic Mass of Cobalt. The chemical symbol for Neptunium is Np. The nucleus consists of 27 protons (red) and 32 neutrons (blue). It is obtained chiefly from the mineral cassiterite, which contains tin dioxide. Argon is the third-most abundant gas in the Earth’s atmosphere, at 0.934% (9340 ppmv). Carbon is one of the few elements known since antiquity. Gallium does not occur as a free element in nature, but as gallium(III) compounds in trace amounts in zinc ores and in bauxite. The chemical symbol for Carbon is C. It is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds. Holmium is a relatively soft and malleable silvery-white metal. In compound form, it occurs in minerals of in copper and nickel. Radon is a radioactive, colorless, odorless, tasteless noble gas. Atomic weight of Cobalt is 58.933194 u or g/mol. Moreover, cobalt is a hard lustrous bluish-gray metal but, on the contrary, the titanium has a silvery grey-white metallic appearance. Nobelium is the tenth transuranic element and is the penultimate member of the actinide series. Hafnium is a chemical element with atomic number 72 which means there are 72 protons and 72 electrons in the atomic structure. Neon is a colorless, odorless, inert monatomic gas under standard conditions, with about two-thirds the density of air. About This Site    Atomic Number Areas covered include atomic structure, physical properties, atomic interaction, thermodynamics, identification, atomic size, crystal structure, history, abundances, and nomenclature. Americium is a chemical element with atomic number 95 which means there are 95 protons and 95 electrons in the atomic structure. The Standard English unit is pounds mass per cubic foot (lbm/ft3). The chemical symbol for Astatine is At. The information contained in this website is for general information purposes only. Bromine is a chemical element with atomic number 35 which means there are 35 protons and 35 electrons in the atomic structure. Units of measure have been defined for mass and energy on the atomic scale to make measurements more convenient to express. We are committed to providing the highest level of customer service. All Rights Reserved. The chemical symbol for Xenon is Xe. The chemical symbol for Barium is Ba. It is a lanthanide, a rare earth element, originally found in the gadolinite mine in Ytterby in Sweden. Americium is a transuranic member of the actinide series, in the periodic table located under the lanthanide element europium, and thus by analogy was named after the Americas. The chemical symbol for Gallium is Ga. Gallium has similarities to the other metals of the group, aluminium, indium, and thallium. Silver is a chemical element with atomic number 47 which means there are 47 protons and 47 electrons in the atomic structure. Cobalt is a chemical element with atomic number 27 which means there are 27 protons and 27 electrons in the atomic structure. In some respects zinc is chemically similar to magnesium: both elements exhibit only one normal oxidation state (+2), and the Zn2+ and Mg2+ ions are of similar size. Titanium is resistant to corrosion in sea water, aqua regia, and chlorine. Lead has the highest atomic number of any stable element and concludes three major decay chains of heavier elements. The chemical symbol for Helium is He. Bromine is the third-lightest halogen, and is a fuming red-brown liquid at room temperature that evaporates readily to form a similarly coloured gas. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Cobalt (Co) is a bluish-white metal that has the atomic number 27 in the periodic table. Germanium is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon. Francium is a highly radioactive metal that decays into astatine, radium, and radon. The chemical properties of this silvery gray, crystalline transition metal are intermediate between rhenium and manganese. There is only one stable isotope of cobalt, which has an atomic weight of 59. Thorium metal is silvery and tarnishes black when exposed to air, forming the dioxide. Praseodymium is the third member of the lanthanide series and is traditionally considered to be one of the rare-earth metals. Argon is mostly used as an inert shielding gas in welding and other high-temperature industrial processes where ordinarily unreactive substances become reactive; for example, an argon atmosphere is used in graphite electric furnaces to prevent the graphite from burning. It is one of the least reactive chemical elements and is solid under standard conditions. Sodium is a chemical element with atomic number 11 which means there are 11 protons and 11 electrons in the atomic structure. Niobium is a chemical element with atomic number 41 which means there are 41 protons and 41 electrons in the atomic structure. Mass numbers of typical isotopes of Cobalt are 59. Francium is the second-least electronegative element, behind only caesium, and is the second rarest naturally occurring element (after astatine). The chemical symbol for Silver is Ag. It is fairly soft and slowly tarnishes in air. The unit of measure for mass is the atomic mass unit (amu). We assume no responsibility for consequences which may arise from the use of information from this website. Caesium is a soft, silvery-gold alkali metal with a melting point of 28.5 °C, which makes it one of only five elemental metals that are liquid at or near room temperature. Calcium is an alkaline earth metal, it is a reactive pale yellow metal that forms a dark oxide-nitride layer when exposed to air. The chemical symbol for Rhodium is Rh. Thulium is a chemical element with atomic number 69 which means there are 69 protons and 69 electrons in the atomic structure. It is a synthetic element (first synthesised at Hasse in Germany) and radioactive. www.nuclear-power.net. is a rare earth element with a metallic silver luster. Cobalt was first discovered in 1735 by George Brandt in Stockholm Sweden. Uranium has the highest atomic weight of the primordially occurring elements. Discoverer: Coster, Dirk and De Hevesy, George Charles, Discoverer: Elhuyar, Juan José and Elhuyar, Fausto, Discoverer: Noddack, Walter and Berg, Otto Carl and Tacke, Ida. Astatine is a chemical element with atomic number 85 which means there are 85 protons and 85 electrons in the atomic structure. Cobalt is also used to make alloys for jet engines and gas turbines, magnetic steels and some types of stainless steels.    Transition Metals It is the heaviest element that can be formed by neutron bombardment of lighter elements, and hence the last element that can be prepared in macroscopic quantities.    Melting Point Cobalt is widely present on the earth crust, in combination with other minerals and in natural water. Atomic Number of Cobalt. It is also the most corrosion-resistant metal, even at temperatures as high as 2000 °C. The chemical symbol for Lithium is Li. Helium is a chemical element with atomic number 2 which means there are 2 protons and 2 electrons in the atomic structure. Gold is thought to have been produced in supernova nucleosynthesis, from the collision of neutron stars. Francium is an alkali metal, that has one valence electron. Cobalt (Co). Atomic number color: black=solid: Group 9 is a group (column) of chemical elements in the periodic table. Thorium is commonly found in monazite sands (rare earth metals containing phosphate mineral). Liquid nitrogen (made by distilling liquid air) boils at 77.4 kelvins (−195.8°C) and is used as a coolant. The chemical symbol for Lanthanum is La. It is a soft, silvery-white alkali metal.    Metalloids Scandium is a chemical element with atomic number 21 which means there are 21 protons and 21 electrons in the atomic structure. Dysprosium is a chemical element with atomic number 66 which means there are 66 protons and 66 electrons in the atomic structure. The density of Hassium results from its high atomic weight and from the significant decrease in ionic radii of the elements in the lanthanide series, known as lanthanide and actinide contraction. Neodymium is not found naturally in metallic form or unmixed with other lanthanides, and it is usually refined for general use. Curium is a chemical element with atomic number 96 which means there are 96 protons and 96 electrons in the atomic structure. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas, the first in the noble gas group in the periodic table. By mass, aluminium makes up about 8% of the Earth’s crust; it is the third most abundant element after oxygen and silicon and the most abundant metal in the crust, though it is less common in the mantle below.