The elements calcium, strontium and barium were put in one group or family on the basis of their similar properties. What were those similar properties?

(a) What was Mendeleev's basis for classification of elements?

(b) Mendeleev's contributions to the concept of a periodic table laid the foundation for the Modern Periodic Table. Give reasons.

Use Mendeleev's Periodic Table to predict the formula of:

(a) hydrides of carbon and silicon

(b) oxides of potassium, aluminium and barium.

Which group of elements was missing from Mendeleev's original periodic table ?