Would you place the two isotopes of chlorine, C1-35 and C1-37 in different slots because of their different atomic masses or in the same slot because their chemical properties are the same? Justify your answer.

Why did Mendeleev leave some gaps in his periodic table ?

In Mendeleev’s periodic table, why was there no mention of noble gases like helium, neon and argon?

State Mendeleev’s periodic law.

What chemical properties of elements were used by Mendeleev in creating his periodic table ?