Question

Write scientific reason.

Mendeleev kept vacant places in the periodic table.

Answer 1

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.