Question
How could the Modern Periodic Table remove various anomalies of Mendeleev's table?
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Answer
(i) The Modern Periodic Table was classified on the basis of atomic number. All isotopes of the same elements have different masses but same atomic number. Therefore, they occupy the same position in the Modern Periodic table.
(ii) When elements are arranged according to their atomic numbers, the anomaly regarding certain pairs of elements in Mendeleev's Periodic Table disappears eg. atomic number of cobalt and nickel are 27 and 28 respectively. Therefore, cobalt will come first and then nickel, although atomic mass of cobalt is greater.
(iii) Elements are classified according to their electronic configuration into different blocks.
(ii) When elements are arranged according to their atomic numbers, the anomaly regarding certain pairs of elements in Mendeleev's Periodic Table disappears eg. atomic number of cobalt and nickel are 27 and 28 respectively. Therefore, cobalt will come first and then nickel, although atomic mass of cobalt is greater.
(iii) Elements are classified according to their electronic configuration into different blocks.
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