CHAPTER 5: PERIODIC TABLE Development of the Periodic Table • i) Substance exist: naturally in elemental form Example: Gold‚ Uranium as unstable compound Example: Radioactive compounds as stable compound (majority) How to know whether a substance is a compound OR an element? ii) iii) • • • Grouping system: 1800: 31 elements identified 1865: 63 elements identified Audi Majdan – DMC 101 – KLIUC 1 • Dmitri Mendeleev: i) ii) iii) iv) Develop a system to group
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THE PERIODIC TABLE HISTORICAL BACKGROUND The idea that all things are elements or combinations of elements can be found in the writings of the ancient Greeks and other early peoples. Although this idea may seem simple‚ it is very difficult to decide if a substance is indeed an element or a compound. There were twelve chemical elements discovered in ancient times‚ but it was not known that they were elements. Another 76 elements were discovered between 1557 and 1925. Many mistakes were made in
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Explore key information about the chemical elements through this periodic table | Group | 1 | 2 | | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | Period | | 1 | 1H1.008 | | 2He4.0026 | 2 | 3Li6.94 | 4Be9.0122 | | 5B10.81 | 6C12.011 | 7N14.007 | 8O15.999 | 9F18.998 | 10Ne20.180 | 3 | 11Na22.990 | 12Mg24.305 | | 13Al26.982 | 14Si28.085 | 15P30.974 | 16S32.06 | 17Cl35.45 | 18Ar39.948 | 4 | 19K39.098 | 20Ca40.078 | | 21Sc44.956 | 22Ti47.867 | 23V50.942 |
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CIS Chem 12/10/12 Unnecessary Title that’s bold‚ italicized‚ and underlined. The periodic table is a chart of elements set up on the bias of atomic numbers‚ chemical properties‚ and their electron configurations. The elements of this chart are organized in families/groups and periods. The word periodic refers to the way the table is ordered‚ which is in periods and families/groups‚ and it looks like this: The green ones are the non-metals‚ the blue ones are alkali metals‚ the red
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Sodium‚ one of many elements in the periodic table is being used in everyday life‚ it is also an essential element within your body. It is just another element‚ but one of the differences is that this element is something that most people consume every day. Sodium has played an important role in everyday life because of its uses in medicine‚ industry‚ and agriculture(Shriver). Sodium was discovered in 1807 by a man named Sir Humphrey Davy. He was well known for his discoveries of most alkali metals
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The Periodic Table By Eric Scerri 1. I just returned home from being interviewed for a new public television program on the mystery of matter and the search for the elements. It was very gratifying to see how keen the film-makers were on understanding precisely how Mendeleev arrived at his famous first periodic table of 1869. This in turn meant that I had to thoroughly review the literature on this particular historical episode‚ which will form the basis of this blog. 2. The usual version of how
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Lesson 3.01: History of the Periodic Table 1. Explain how scientific observations led to the development of‚ and changes to‚ the periodic table. Dmitri Mendeleev- first periodic table‚ organized 63 known elements according to properties‚ organized into rows and columns. He wrote names‚ mass and chemical properties on each. Julius lothar Meyer- independently worked in German ‚ similar to Mendeleev Henry Gwyn Jeffrey’s Moseley: worked with Ernest Rutherford experimented with 38 metals‚ he found that
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Promethium‚ Pm‚ is the 61st element on the Periodic Table. It was discovered in 1945 by Jacob A. Marinsky. It’s a metal‚ and named after the Greek God Prometheus. It is not naturally occurring‚ but can survive outside of a lab. Promethium has an atomic number of 61‚ which is the number of protons. Its atomic mass‚ protons+neutrons‚ is 145u. It is an isotope. This means that it has a different number of neutrons (84) than the number of electrons and protons (61). Every element changes states
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It is in the d-block and it is a transition metal. Technetium is in the 7th group in the periodic table because it has 1 electron on its last shell. Also it is in the 5th period in the periodic table because it has 5 shells. Number of energy levels of Technetium is 5. Its electron shells are 2‚8‚18‚14‚1 as it is in the picture. Firstly‚ Russian chemist Dmitri Mendeleev‚ who is the creator of the periodic table‚ predicted Technetium’s existence. He called it eka-manganese because there was a missing
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The Development of the Periodic Table Although Dmitri Mendeleev is often considered the ‘father’ of the periodic table‚ the work of many scientists contributed to its present form. Between 1817-1829‚ Johann Dobereiner began to group elements with similar properties in to groups of three or triads. This began when he noticed that the atomic weights of strontium (Sr) were halfway between Calcium (Ca) and Barium (Ba). He stated that nature contained triads of elements in which the middle element
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