Question

Mendeleev classified elements in –
(a) increasing order of atomic groups
(b) eight periods and eight groups
(c) seven periods and nine groups
(d) eight periods and seven groups

Answer 1

Answer:

a. increasing order of atomic group

Answer 2

Seven periods and eight groups.

Explanation:

The most significant contribution towards the development of periodic table was made by the Russian chemist Dmitri Mendeleev. He was the first scientist to make a periodic table similar to the one used today. Mendeleev arranged the elements in increasing order of atomic weights in seven periods and eight groups.

None of the options given match the answer.