Question
Merits of Modern Periodic table over Mendeleev's periodic table.
✓
Answer
In Modern Periodic table elements were arranged on basis of their atomic number.
(i) All isotopes of the same element have different masses but same atomic number. Therefore, they occupy the same position in the Modern Periodic table.
(ii) When the elements are arranged according to their atomic numbers, the anomaly regarding certain pairs of elements in Mendeleev's periodic table disappears, e.g. atomic numbers of Cobalt and Nickel are 27 and 28 respectively. Therefore, Cobalt will come first and then Nickel, although its atomic mass is greater.
(iii) Elements are classified according to their electronic configuration into different blocks.
(i) All isotopes of the same element have different masses but same atomic number. Therefore, they occupy the same position in the Modern Periodic table.
(ii) When the elements are arranged according to their atomic numbers, the anomaly regarding certain pairs of elements in Mendeleev's periodic table disappears, e.g. atomic numbers of Cobalt and Nickel are 27 and 28 respectively. Therefore, Cobalt will come first and then Nickel, although its atomic mass is greater.
(iii) Elements are classified according to their electronic configuration into different blocks.
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