Chemistry
Answer
The criteria used by Mendeleev in proposing his periodic table was the atomic masses of elements. He classified elements according to Mendeleev's Periodic Law. Mendeleev's Periodic Law states that physical and chemical properties of elements are a periodic function of their atomic masses.
Related Questions
How does the number of (i) valence electrons (ii) valency; vary on moving from left to right:
(a) in the second period of a periodic table?
(b) in the third period of a periodic table?
How do atomic structures (electron arrangements) change in a period with an increase in atomic numbers, moving from left to right?
How are the positions of Cobalt and Nickel resolved in the Modern periodic table?
Cl35 and Cl37 are two different atoms. Where would they be placed in the periodic table.