Periodic Classification of Elements - 884 Words

PERIODIC CLASSIFICATION OF ELEMENTS Introduction There are 115 elements that are known at present. Some elements have similar properties whereas some others have completely contrasting properties Scientists began to look for some pattern in the properties of these elements Dobereiner’s triads In 1817, Johann Wolfgang Dobereiner, a German chemist, classified elements into groups based on their properties. He kept all elements having similar properties in one group. Most of his groups had three elements each. Thus, he called these groups as triads He also gave a law known as the Law of Triads. It states that when three elements in a triad are listed in the increasing order of their atomic masses, the atomic mass of the middle†¦show more content†¦He had predicted that some elements were yet to be discovered. He left these gaps deliberately so that these undiscovered elements could get a place in his periodic table. Mendeleev named the undiscovered elements using the Sanskrit word Eka (meaning one) as a prefix, with the name of the preceding element in the same group. For example, gallium was not discovered in Mendeleev’s time. Therefore, he left a gap for it in his periodic table and named it Eka-aluminium. He also predicted the properties of these undiscovered elements based on their positions in the periodic tab . It can be clearly observed from the table that Mendeleev’s predictions were almost exact. This extraordinary achievement made Mendeleev’s periodic table very popular. †¢ Noble gases were not discovered at the time when Mendeleev gave the periodic table. These were discovered in recent times as they are very inert and are present in very low concentrations in the atmosphere. When these gases were finally discovered, they got a place in his periodic table as a separate column. The accommodation of these gases in the periodic table did not disturb the positions of other elements. This underlined the strength of Mendeleev’s periodic table Limitations of Mendeleev’s periodic table: 1. Hydrogen’s position was not justified in Mendeleev’s periodic table. He positioned hydrogen in the first column above alkali metals. He did soShow MoreRelatedThe Classification Of Elements Of The Periodic Table1996 Words   |  8 PagesThe periodic table shows the classification of elements. It shows the elements’ atomic numbers, masses, and symbols for each element. Elements are placed into rows and columns. The rows are called periods, and the columns are called groups. These help classify where the elements go on the periodic table. For example, the elements in the very last group on the periodic table are known as inert and noble gases. The modern periodic table resulted from trial, error, and succession. As more elementsRead MoreDigital Signal Processing Quiz1620 Words   |  7 Pages (DIGITAL SIGNAL PROCESSING) 1.What are the basic elements of digital signal processing. List the advantages of digital signal processing over Analog signal processing? 2. Give the classification of signals (a) Continuous time signals and discrete time signals. (b) Deterministic and Non-Deterministic signals (c) Periodic and Aperiodic signals (d) Even and Odd signals (e) Energy and Power signal 3.Determine whether the followingRead MoreHistory Of The Periodic Table1711 Words   |  7 PagesHistory of the Periodic Table Austin Smith LSG5 Scientists all around the world have attempted to group, sort and organise elements together for hundreds of years, with initial classification systems dating decades before the dawn of an actual table in the nineteenth century. An example of early work prior to the 1800s is Antoine Lavoisier and partners Antoine Fourcroy, Louis-Bernard Guyton de Morveau and Claude-Louis Berthollet’s list of elements. While this one dimensional system documented allRead MorePhysics Of The Mass Atomic Mass964 Words   |  4 Pagesthe periodic table is table that represents elements as symbols e.g. (He) represents helium, each symbol have a number above the symbols and one at the bottom of the symbols The number at the top represents the relative atomic mass (protons plus neutrons) there is also a number at the bottom of the symbol which represents the number of protons. How elements are organised in groups periods and blocks 2. Periods Elements that are arranged in horizontal rows, in the first row all the elements haveRead Moreâ€Å"The Elements, If Arranged According To Their Atomic Weights1237 Words   |  5 Pagesâ€Å"The elements, if arranged according to their atomic weights exhibit an apparent periodicity of properties.†-Original quote from Dmitri Mendeleev. Dmitri Mendeleev was known for assembling the final periodic table and he predicted the arrangement of the elements. It is said in the Kahn Academy article that Dmitri Mendeleev got the idea for the Periodic Table from playing solitaire. He also envisioned the periodic table in a dream after a three day work binge. He also was known for finding thirtyRead MorePhysics Of The Periodic Table1506 Words   |  7 PagesThe Periodic Table Chemically speaking, the periodic table was a major factor in improving the study of elements, in which then the study of these elements expands into broader studies such as atoms and sub-atoms. This essay will talk about the history of the development of the periodic table and will further discuss the how and why it was created. Moreover, it will include the history of various chemists that contributed in the improvement of the table such as Johann Wolfgang Dà ¶bereiner, John NewlandsRead MoreHistory Of The Periodic Table Of Elements1664 Words   |  7 Pages10/24/14 History of the Periodic Table of Elements The construction of the Periodic Table of Elements was prior to the discovery of the individual elements. Elements such as silver, gold, tin, copper, lead and mercury have been known for centuries. In 1649, the first scientific discovery of an element was made by Hennig Brand when he discovered phosphorous. Prior to Brand’s discovery, chemists had acquired an immense body of understanding concerning the properties of elements and their compounds forRead MoreDmitri Mendeleev: The Development of the Periodic Table Essay1529 Words   |  7 PagesDevelopment of the Periodic Table Introduction: The Periodic Table of Elements is a table that arranges all known chemical elements by order of their atomic numbers. During the 1600s, vast amounts of knowledge about the properties of elements and their compounds were discovered and by 1869 63 elements had been discovered. As more and more elements were discovered, scientists began to recognise similarities between their properties and began to devise means of classification. Thus the periodic table of elementsRead MoreThe Development Of The Periodic Table1698 Words   |  7 Pagesthe Periodic Table including its origins, the original data used to construct it and the predictions made after its construction. (Include references to the contributions made by Antoine Lavoisier, Johann Dobereiner, John Newlands, Dmitri Mendeleev, Lothar Meyer, William Ramsay, Henry Moseley, J.J. Thomson and Niels Bohr. In 1803 a man by the name of John Dalton Proposed that matter was comprised of atoms that were very simple and solid with no structure. He also put forward that each element wasRead MoreHistory And Development Of The Periodic Table2227 Words   |  9 Pages History and Development of the Periodic Table Ben Madden 10B â€Æ' Part A: Timeline of the Periodic Table 0 Ancient Greeks believed that everything was made of four elements mixed together in different proportions. These elements were fire, water, air and earth. 1661 Robert Boyle had an assumption that an element was an individual substance that could not be broken down further into a smaller substance through the process of a chemical reaction. Boyle’s assumption is considered to be the