11th Class Chemistry Classification of Elements and Periodicity in Properties

  • question_answer 104)   In what manner is the long form of periodic table better than Mendeleev's periodic table? Explain with examples.


      Superiority of the Long form of the Table over Mendeleev?s Table: (i) This table is based on a more fundamental property, i. e atomic number. (ii) It correlates the position of the elements with its electronic configuration more clearly. (iii) The completion of each period is more logical. In a period as the atomic number increases, the energy shells are gradually filled up until an inert gas configuration is reached. It eliminates the even and odd series of IV, V, VI and VII periods of Mendeleev's periodic table. (iv) The position of VIIIth group is appropriate in this table. All the transition elements have been brought in the middle as the properties of transition elements are intermediate between s- and p-block elements. (v) Due to separation of two subgroups, dissimilar elements do not fall together. One vertical column accommodates elements with same electronic configuration thereby showing same properties. (vi) In this table a complete separation between metals and non-metals has been achieved. The non-metals are present in the upper right comer of the periodic table. (vii) There is a gradual change in properties of the elements with increase in their atomic numbers, i.e., periodicity of properties can be easily visualised. The same properties of recurrence in properties occur after the intervals of 2, 8, 8, 18, 18 and 32 elements which indicates the capacity of various periods of the table. (viii) This arrangement of elements is easy to remember and reproduce.

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