• Question: What is the periodic table?

    Asked by 322bera39 to Colin, John, Kevin, Shikha, Triona on 10 Nov 2014.
    • Photo: Shikha Sharma

      Shikha Sharma answered on 10 Nov 2014:

      Hi 322bera39,
      As a school student I was always amazed to see that how Mendleev arranged so many elements in a table.
      Periodic table is the arrangement of elements in which they are arranged left to right and top to bottom in order of increasing atomic number. The various rows are called periods whereas the columns are known as group. The first idea of arranging these elements was given in 1869 by a Russian chemist named Dmitri Mendeleev. Basically, he set the elements in order of atomic weight, and then grouped them into rows and columns based on their chemical and physical properties. Interestingly, Mendeleev had no idea what atoms were made of or why they behaved as they did. Not only this based on the gaps in his table, he even succeeded in predicting the existence and properties of several new elements.
      Isn’t that great?
      The period number of an element signifies the highest energy level an electron in that element occupies (in the unexcited state). Elements in the same column on the periodic table have identical valance electron configurations and thus behave in a similar fashion chemically.

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