Without knowing the electronic configuration of the atoms of elements Mendeleff still could arrange the element nearly close to the arrangements in the Modern periodic table. How can you appreciate this?

Mendleeff’s periodic table

i. He arranged the elements in a systematic order of their increasing atomic masses.

ii. He also discovered law which stated that “the physical and chemical properties of the elements are periodic function of their atomic masses.

iii. There are eight vertical columns called as groups.

iv. The horizontal rows in table called as periods.

v. Based on the arrangement, he believed that some new elements would be discovered definitely.

vi. He predicted the properties of these elements in advance.

vii. After the elements were discovered, his predicted properties were almost the same as observed properties.

viii. It was the extraordinary thinking of Mendleeff that made the chemist to accept the periodic table.