Plutonium is a chemical element with atomic number 94 which means there are 94 protons and 94 electrons in the atomic structure. Global Trends in Energy Technology Innovation, Hydrogen Fuel Cells: Energy of the Future, From Bhopal to Hazardous Waste Compliance, Love Canal NY: Grownups Don't Do Blue Goo, New Orleans, Hurricane Katrina & the Oil Industry, Environmental Justice and the NIMBY Principle. Thulium is the thirteenth and third-last element in the lanthanide series. 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. However, the metal is dangerous to handle because it and its compounds are both toxic and radioactive. Electron configuration 5f 2 6d 1 7s 2: Electrons per shell: 2, 8, 18, 32, 20, 9, 2: Physical properties; Phase at STP: solid: Melting point: 1841 K (1568 °C, 2854 °F) Boiling point: 4300 K (4027 °C, 7280 °F) (?) Natural boron consists primarily of two stable isotopes, 11B (80.1%) and 10B (19.9%). For example, silicon has nine possible integer oxidation states from −4 to +4, but only -4, 0 and +4 are common oxidation states. Multiple-site search is loading. Francium is the second-least electronegative element, behind only caesium, and is the second rarest naturally occurring element (after astatine). As the most electronegative element, it is extremely reactive: almost all other elements, including some noble gases, form compounds with fluorine. The electron configuration is the distribution of electrons of an atom or molecule (or other physical structure) in atomic or molecular orbitals. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal. Silicon is a hard and brittle crystalline solid with a blue-grey metallic lustre, it is a tetravalent metalloid and semiconductor. Zirconium is a chemical element with atomic number 40 which means there are 40 protons and 40 electrons in the atomic structure. Protactinium was first identified by Kasimir Fajans and O.H. Each entry has a full citation identifying its source. Technetium is the lightest element whose isotopes are all radioactive; none are stable. Curium is a hard, dense, silvery metal with a relatively high melting point and boiling point for an actinide. Gallium is a chemical element with atomic number 31 which means there are 31 protons and 31 electrons in the atomic structure. This metal has around five isotopes with their mass numbers ranging between 212 to 238 and protactinium 231 is considered to be the most stable isotope with a half-life of about 32,760 years. The chemical symbol for Lanthanum is La. Promethium is one of only two such elements that are followed in the periodic table by elements with stable forms. In addition technical terms are linked to their definitions and the menu contains links to related articles that are a great aid in one's studies. Every solid, liquid, gas, and plasma is composed of neutral or ionized atoms. Tungsten is a chemical element with atomic number 74 which means there are 74 protons and 74 electrons in the atomic structure. 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. It is one of the least reactive chemical elements and is solid under standard conditions. The chemical symbol for Scandium is Sc. The chemical symbol for Yttrium is Y. Yttrium is a silvery-metallic transition metal chemically similar to the lanthanides and has often been classified as a “rare-earth element”. The ninth member of the lanthanide series, terbium is a fairly electropositive metal that reacts with water, evolving hydrogen gas. The chemical symbol for Helium is He. It occurs in all uranium ores to the extent of 0.34 part per million of uranium. Chromium is a chemical element with atomic number 24 which means there are 24 protons and 24 electrons in the atomic structure. The chemical symbol for Oxygen is O. Iron is a metal in the first transition series. Understand the noble gas electron configuration. Pure radium is silvery-white alkaline earth metal. Only about 5×10−8% of all matter in the universe is europium. Gold is a bright, slightly reddish yellow, dense, soft, malleable, and ductile metal. Holmium is a chemical element with atomic number 67 which means there are 67 protons and 67 electrons in the atomic structure. Beryllium is a hard, grayish metal naturally found in mineral rocks, coal, soil, and volcanic dust. Zirconium is mainly used as a refractory and opacifier, although small amounts are used as an alloying agent for its strong resistance to corrosion. Nevertheless protactinium also shows a strong horizontal analogy with thorium and uranium in also displaying the +4 oxidation state, something that Mendeleev does not seem to have anticipated. Protactinium is a radioactive actinide group metal with the atomic symbol Pa, atomic number 91, and atomic weight 231. Oxidation state 0 occurs for all elements – it is simply the element in its elemental form. Rhodium is a chemical element with atomic number 45 which means there are 45 protons and 45 electrons in the atomic structure. Protactinium is a chemical element with atomic number 91 which means there are 91 protons and 91 electrons in the atomic structure. The subshells have a distinct shape and configuration, in which the electrons move freely. For atoms with many electrons, this notation can become lengthy and so an abbreviated notation is used. When an electron is added to a neutral atom, energy is released. Pa-231 is the most abundant naturally occurring isotope. (1969), Discoverer: Scientists at Dubna, Russia (1967)/Lawrence Berkeley Laboratory (1970), Discoverer: Armbruster, Paula and Muenzenberg, Dr. Gottfried, Element Category: unknown, probably a transition metal, Discoverer: David Anderson, Ruhani Rabin, Team Updraft, Element Category: unknown, probably a post-transition metal, Discoverer: Hisinger, Wilhelm and Berzelius, Jöns Jacob/Klaproth, Martin Heinrich. Discoverer: Davy, Sir H. and Thénard, L.-J. Thomas Jefferson. The particular isotope they found, protactinium-234 m, has a half-life of about 1.17 minutes.They named the element brevium, meaning brief, and then continued with their studies. The chemical symbol for Titanium is Ti. In the periodic table, the elements are listed in order of increasing atomic number Z. Electron configuration of Protactinium is [Rn] 5f2 6d1 7s2. In the periodic table, potassium is one of the alkali metals. The nucleus consists of 91 protons (red) and 140 neutrons (blue). A number of protactinium compounds are known, some of which are colored. It has remarkable resistance to corrosion, even at high temperatures, and is therefore considered a noble metal. Oxidation states are typically represented by integers which may be positive, zero, or negative. Very soft and malleable, indium has a melting point higher than sodium and gallium, but lower than lithium and tin. 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. Arsenic is a metalloid. Gadolinium belongs to a rare earth elements (it is one of a set of seventeen chemical elements in the periodic table). Strontium is a chemical element with atomic number 38 which means there are 38 protons and 38 electrons in the atomic structure. Knowledge of the electron configuration of different atoms is useful in understanding the structure of the periodic table of elements. Lead is a heavy metal that is denser than most common materials. The element is superconductive below 1.4K. The Kossel shell structure … The chemical symbol for Astatine is At. 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). Protactinium atoms have 91 electrons and the shell structure is 2.8.18.32.20.9.2. Scandium is a silvery-white metallic d-block element, it has historically been sometimes classified as a rare-earth element, together with yttrium and the lanthanides. It is also sometimes considered the first element of the 6th-period transition metals and is traditionally counted among the rare earth elements. It is the fifth most abundant element in Earth’s crust and the third most abundant metal, after iron and aluminium. It could be part of the main body, but then the periodic table would be rather long and cumbersome. The chemical symbol for Gold is Au. It is a Block F, Group 3, Period 7 element. Actinium gave the name to the actinide series, a group of 15 similar elements between actinium and lawrencium in the periodic table. Neon is a chemical element with atomic number 10 which means there are 10 protons and 10 electrons in the atomic structure. Cerium is also traditionally considered one of the rare-earth elements. Titanium is a lustrous transition metal with a silver color, low density, and high strength. and Gay-Lussac, L.-J. If you continue to use this site we will assume that you are happy with it. The chemical symbol for Tantalum is Ta. Thorium - Electron Configuration and Oxidation States - Th, Actinium - Electron Configuration and Oxidation States - Ac, Radium - Electron Configuration and Oxidation States - Ra, Thorium – Electron Configuration and Oxidation States – Th, Uranium – Electron Configuration and Oxidation States – U. Atomic Structure of Protactinium. Electron Configuration Isotopes Protactinium has no stable isotopes . 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. Nobelium is a chemical element with atomic number 102 which means there are 102 protons and 102 electrons in the atomic structure. Compact Fluorescent Lights (CFLs): Are They Worth the Switch? The chemical symbol for Arsenic is As. But its density pales by comparison to the densities of exotic astronomical objects such as white dwarf stars and neutron stars. 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