The Periodic Table Menu
Carlito Roby
WebElements: THE periodic table on the WWW [www.webelements.com]
Copyright 1993-2024 Mark Winter [ The University of Sheffield and WebElements Ltd, UK]. All rights reserved.
Our policy is to only create individual element pages for elements on our periodic table that have been officially recognized and named by the International Union of Pure and Applied Chemists (IUPAC). Likewise we only list unnamed elements on our table above whose discovery has been tentatively recognized by IUPAC. Thus at this point in time we have not created individual element pages for elements 114 and above as they have not been officially named. Likewise even though some scientists have claimed to have isolated elements 113 and 115 we do not list these two elements because their discovery has not yet been acknowledged by IUPAC.
The "discovery" of element 118 is still very much in debate. It was reportedly isolated in 1999 by the Ninov et al. Berkeley collaboration, but that report was retracted in 2002. In Oct. 2006 it was again reportedly isolated by scientists from the Lawrence Livermore National Laboratory and their Russian partners at the Dubna nuclear research center in Russia, but IUPAC has not yet commented on this.
On December 1st 2011, the IUPAC announced the proposed names for elements 114 and 116. Element 114 would be named flerovium with the symbol Fl, while element 116 would be named livermorium with the symbol Lv. There will be a five month comment period for the new names. If all goes well the names will become official in May of 2012.
Periodic Table - A tabular arrangement of elements in rows (periods) and columns (groups) in the order of their atomic numbers. The atomic number indicates the number of electrons in the atoms of an element. Electron configurations of the elements help explain the recurrence of physical and chemical properties. A period consists of the elements in any one horizontal row of the periodic table. A group consists of the elements in any one column of the periodic table. When the elements are arranged by atomic number in the periodic table, their physical and chemical properties vary periodically.
The earliest attempts to classify matter, from metals to minerals, were based on the idea of essential qualities, or elements. Ancient Greek philosophers had four: air (hot and wet), water (cold and wet), earth (cold and dry) and fire (dry and hot).
The idea had been in the air since the first international conference of chemistry in 1860 at Karlsruhe, Germany. At this meeting, standard values for the atomic weights of the 60 elements then known had been agreed by the world's leading chemists.
Even the famous version you might know provokes fierce debate among chemists about where certain groups or elements, like hydrogen, should be placed. And as new elements are added, it will continue to evolve.
In recent decades, the Internet has opened up the practice of periodic table making to a wider public. As well as alternative forms, there are alternative contents: you can find periodic tables of almost anything, from wine to football.
The periodic table is way of ordering the chemical elements by atomic number, from the element with the lowest atomic number, hydrogen, to the element with the highest atomic number. The atomic number of an element is the number of protons in the nucleus of an atom of that element.
Chemists have always looked for ways of arranging the elements to reflect the similarities between their properties. The modern table lists the elements in order of increasing atomic number (the number of protons in the nucleus of an atom). Historically, however, relative atomic masses were used by scientists trying to organise the elements. This was mainly because the idea of atoms being made up of smaller sub-atomic particles (protons, neutrons and electrons) had not been developed. The basis was well established and even used to predict the properties of undiscovered elements long before the concept of the atomic number was developed.
The atomic number of an element tells you several pieces of information about the element. First off the atomic number tells you the order it presents itself in the periodic table. Looking at the example above, the atomic number of carbon is 6 so it is the 6th element found on the periodic table. In addition to this the number 6 tells you the total number of protons found in the nucleus of this element and the total number of electrons found in its atomic orbitals
The atomic mass or average atomic mass of an element is the average mass of all the found isotopes of the element. The number that is written on the periodic table is the weight of the most common isotope found in nature or in the lab.
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You may also use the color-coded periodic table chart with names, symbols, and atomic weights to find specific information you need for your work. Easy-to-use filters allow you to sort by metals, nonmetals, physical states, group, period, and more.
These elements are very reactive, and usually occur in nature already combined with other elements. They have a silver-like luster, high ductility, and are excellent conductors of electricity and heat. Alkali metals have low melting points, ranging from 28.5 to 179C.
Alkaline Earth metals form Group 2 of the periodic table. Except for radium, all of the elements in this group are used in commercial applications. Magnesium and calcium are two of the six most common elements on Earth, and are essential to some geological and biological processes.
These elements have a shiny gray-white appearance. They are good conductors of electricity and have higher melting and boiling points than the alkali metals. Melting points range from 650 to 1,287C and boiling points range from 1,090 to 2,471C.
Similar to the metals, transition metals are malleable and ductile, conduct heat and electricity, and form positive ions. However, these elements are more electronegative and more likely to form covalent compounds. Transition metals can form useful alloys with other transition or metallic elements.
The post-transition metals share many similarities with the metals, including malleability, ductility, and conductivity of heat and electricity, but are usually softer and have lower melting and boiling points than the transition metals. They have poor mechanical strength, form covalent bonds, and display acid-base amphoterism.
Lanthanides oxidize rapidly in moist air, dissolve quickly in acids, and react slowly with oxygen at room temperature. These elements are used in superconductors and hybrid car components, primarily as magnets and batteries. They are also used in the production of specialty glass.
The 15 metallic elements with atomic numbers 89 to 104, actinium through lawrencium, are referred to as the actinides. All of these elements are radioactive, relatively unstable, and release energy in the form of radioactive decay. However, they can form stable complexes with ligands, such as chloride, sulfate, carbonate, and acetate.
Their radioactivity, toxicity, pyrophoricity, and nuclear criticality make the actinides hazardous to handle. Uranium and plutonium have been used in nuclear plants and in atomic weapons. Some actinides occur naturally in seawater or minerals, but the actinides with atomic numbers 95 to 104 are man-made, created using particle accelerators.
The most commonly recognized metalloids include boron, silicon, germanium, arsenic, antimony, and tellurium. Their properties are a mixture of or fall between those of metals and nonmetals, and the number of elements included in this category can vary.
Metalloids have a shiny appearance like metals, but behave more like non-metals. They have fair electrical conductivity and brittle structures. Chemically, they have intermediate ionization energies and electronegativity values, and form amphoteric or weakly acidic oxides. Metalloids are used in alloys, biological agents, catalysts, flame retardants, glass, optical storage and optoelectronics, pyrotechnics, semiconductors, and electronics.
Halogens are the non-metallic elements found in group 17 of the periodic table: and include fluorine, chlorine, bromine, iodine, and astatine. They are the only group whose elements at room temperature include solid, liquid, and gas forms of matter. When halogens react with metals, they produce a range of useful salts, including calcium fluoride, sodium chloride, silver bromide, and potassium iodide.
Since halogens are one electron short of having full shells, they can combine with many different elements. They are highly reactive and can be lethal in concentrated amounts. Commercially, halogens are used in disinfectants, lighting, and drug components.
When Dmitri Mendeleev created the periodic table in the late 19th century, he grouped elements by atomic weight. When grouped by weight, the behavior of the elements appeared to occur in regular intervals or periods. The columns of the modern periodic table represent groups of elements and rows represent the periods. The groups are numbered one through 18. Elements in the same group can be expected to behave in a similar way because they have the same number of electrons in their outermost shell.
Hydrogen comprises more than 90% of the atoms in the universe and was first recognized as a distinct substance in 1776. On earth, it is most commonly found combined with oxygen as water, and is also present in living plants, petroleum, coal, and other organic matter.
Liquid hydrogen is used in cryogenics and to study superconductivity. Isotopes deuterium and tritium are used as nuclear fusion reactor fuel. Tritium is produced by nuclear reactors and is used to make hydrogen bombs.
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