since the periodic table was found no new elements added?
817102
They're constantly adding new ones.  The new ones are synthetically created by bombarding already existing elements with neutrons.  Apparently, they're up to atomic no. 118, now:\n\nhttp://www.webelements.com/webelements/scholar/
36750
I don't think there are any with that atomic mass. At least not on my periodic table.
657306
Some elements are not natural to earth, and were brought here by meteroites and such things that crashed into Earth (and still crash into today). Some of the heavy metals, especially...certain other elements. \n\nSome are just unstable elements or compounds, and so they break down rather quickly, especially the radioactive ones where their half-lives are as short as days or minutes. Or are man-made.\n\nYou also have to go down to the basics of Chemistry. Some elements HATE to be alone, they are unstable in their groundstates, and they like to bond with other atoms to form compounds.\n\n"Elements 58 to 71 (on the periodic table) are known as lanthanide or rare earth elements. These elements are found on earth in only very small amounts.\nElements 90 to 103 are known as the actinide elements. They include most of the will known elements which are found in nuclear reactions. The elements with larger atomic numbers than 92 do not occur naturally. They have all been produced artificially by bombarding other elements with particles.\n\n\nThere are a wide array of reason as to why some elements are more rare. I hope this shed a little bit of light to your question.
905961
Nobody knows the answer to this exept for Mendeleev himself, and he isn't talking. The first periodic table had 64 elements, although 3 or 4 of those were still purely theoretical. Since there were more than 50 in the first periodic table, you can't really discuss the first 50 added very well. Several models of organization were proposed, but there were around 60 known elements before it was deemed necessary to organize them. Only Mendeleev's used periodicity, and it is the closest to our modern periodic table.\n\nThe only 2 elements in my periodic table are:\n\nWOMANIUM (XX)\nPhysical properties: Generally soft and round in form. Boils at nothing and may freeze any time. Very bitter if not used well.\nChemical properties: Very active and highly unstable. Possesses strong affinity with gold, silver, platinum, and precious stones. Violent when left alone. Turns slightly green when placed next to a better specimen.\nUsage: An extremely good catalyst for dispersion of wealth.\nCaution: Highly explosive in inexperienced hands!\n\nMANIUM (XY)\nPhysical properties: Solid at room temperature but gets bent out of shape easily. Difficult to find a pure sample. Due to rust, aging samples are unable to conduct electricity as easily as young samples.\nChemical properties: Attempts to bond with XX any chance it can get. Also tends to form strong bonds with itself. Becomes explosive when mixed with Childrium for prolonged period of time.\nUsage: Possibly good methane source.\nCaution: In the absence of XX, this element rapidly decomposes and begins to smell.
463143
In 1869 when the periodic table first was created by Mendeleev.  The element was first isolated in 1774.
471015
google it and type 'periodic table, first twenty elements'\nn u'll get sumthing, far quicker than lettin sum1 write them up 4 u.
728444
Usually the discoverer names it, but the final decision is up to IUPAC, the International Union of Pure and Applied Chemistry.  The heaviest known elements were discovered during the Cold War, and of course the Americans and Soviets both claimed to have discovered them first and tried to name them after their scientists, so IUPAC stepped in and named the new elements with a numeric code.  That's why those elements have such odd names, like unnilquadium or unnilpentium.  It's just Latin for "element number 104" or "element number 105".  Some periodic tables still use the American names but most use IUPAC's.
137403
the periodic table is great because it ditinguishes the different shells (s, p, d and f) that are filled as you add electrons. eg. He has 2 s electrons (full shell)\nNe has 1s2, 2s2 and 2p6 (full shell).\nIt gets a little more complicated at d electrons (transition metals) but Mendeleev did a great first shot.
59388
The periodic table as of Oct. 2005 according to IUPAC shows 111. But the elements with atomic numbers 112, 114, and 116 have been reported but not have not been fully authenticated as of September 2003 (Pure Appl. Chem. 75(10), pp. 1601-1611, 2003).
84972
Dmitri Mendeleev, also spelt Dmitry Mendeleyev, middle name (patronymic) Ivanovich, a Siberian-born Russian chemist, was the first scientist to make a periodic table much like the one we use today. Mendeleev arranged the elements in a table ordered by atomic mass. On March 6, 1869, a formal presentation was made to the Russian Chemical Society, entitled The Dependence Between the Properties of the Atomic Weights of the Elements. His table was published in an obscure Russian journal but quickly republished in a German journal, Zeitschrift für Chemie, in 1869.\n\nIn 1913, Henry Moseley found a relationship between an element's X-ray wavelength and its atomic number. Before this discovery, atomic numbers were just random numbers based on an element's atomic weight. Moseley's discovery showed that atomic numbers were not arbitrary but had an experimentally measurable basis.\n\nMosley's research also showed that there were gaps in his table at atomic numbers 43 and 61 which are now known to be radioactive and not naturally occurring. Following in the footsteps of Dmitriy Mendeleyev, Henry Moseley also predicted new elements.\n\nWalter Russell produced yet another periodic table in 1926, complaining that the widely accepted table did (as it does indeed) have gaps and exceptions which are not scientific. This table predicted the existence of several yet-undiscovered elements, including tritium, deuterium, plutonium, and neptunium. This table never gained widespread acceptance, though it's still touted by a devout following for its "completeness", lacking the need for special exceptions of the official table.
68825
There is no solution. It has not been discovered yet.
699921
It will always have the same number of protons per atom... it protons are added or taken away, it won't be gold anymore.
1157452
The first 92 elements of the periodic table occur naturally (from hydrogen to uranium).\n\nBTW, in reference to earlier poster, some of the naturally occurring elements (radon, radium, uranium, others) are radioactive, as well.
223202
goto http://www.webelements.com/ or better stillhttp://www.schoolscience.co.uk/periodictable.html run over the element with your mouse it tells you what it is
878902
The elements don't match up, so it can't be done.  Nitrogen does not appear on the right side, nor oxygen on the left.
713783
The alkali metals and the alkali earth metals are the the first columns appearing the periodic table.  Each of the elements found in these groups has the ability to lose electrons, thus making them cations (they become positively charged by losing a negative charge).\n\nHowever, all elements need to have a complete valence shell, which means that their outermost electron shell must be full.  Any deficiency or excess of electrons in their outermost ring will make the elements either lose the excess electrons or gain more in order to completely fill their outermost electron shell.\n\nHydrogen, which is the first element in the periodic table, has only 1 electron.  If Hydgrogen donates this electron, it becomes known as a proton, usually denoted as H+.  If you are writing out equations, H+ will work fine.  Remember, with only one electron, a Hydrogen atom is only composed of one electron and one proton.  \n\nOther than Hydrogen, almost no element will completely lose all of its electrons.
714340
look up the periodic table...duh