Question

At the time of Mendeleev, the number of elements known was
(a) 63
(b) 65
(c) 62
(d) 64​

Answer 1

Answer:

$\huge\pink{AnSwer}$

==>(a) 63

Answer 2

Explanation:

At the time of Mendeleev, the number of elements known was

correct answer is (a) 63

To put some order into his study of chemical elements, Mendeleev made up a set of cards, one for each of the 63 elements known at the time. Mendeleev wrote the atomic weight and the properties of each element on a card. He took the cards everywhere he went.