Question
Write scientific reason.
Mendeleev kept vacant places in the periodic table.

Answer

  1. In Mendeleev’s periodic table, the elements are arranged in increasing order of their atomic masses such that chemically similar elements are placed together in a group.
  2. However, while arranging the elements, Mendeleev kept vacant places in the periodic table for elements not discovered till then.
  3. Three of these unknown elements were given the names eka-boron, ekaaluminium and eka-silicon from the known neighbours.
  4. The atomic masses of these elements were indicated as 44, 68 and 72, respectively. He also predicted their properties.

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