Which chemical compounds of elements were used by Mendeleev to gauge their chemical similarities?
(A) Oxides (B) Chlorides (C) Hydrides (D) Sulphites
A, C
A, B, C
B, D
A, B, C, D
Mendeleev considered oxides and hydrides of elements for classifying their properties.
What physical and chemical properties of elements were used by Mendeleev in creating his periodic table? List two observations which posed a challenge to Mendeleev's Periodic Law.