Question

When Mendeleev developed his periodic table, chemists knew nothing about the internal structure of atom. His classification was based on their atomic wetghts. Several anomalies persisted in the table with regard to the correct order of atomic weights of
(i) `K`adn`Ar` (ii) `Co`and`Ni`
(iii) `Te`and`I`
A. `(i),(ii)`
B. `(i),(ii),(iii)`
C. `(ii),(iii)`
D. `(i),(iii)`

Answer 1

Correct Answer - B
Atomic mass of `Ar(39.95u)` is greater than thet of `k(39.10u)` but `K` is placed after `Ar`. Similarly for others.