Periodic Classi...

As we move along a period, the valency of elements :

What is the valency of magnesium with atomic number $$12$$?

_________ were not included in Mendeleev's periodic table.

Which of the following statements are correct about Mendeleev's periodic table?
i) It is based on increasing order of atomic numbers.
ii) Mendeleev corrected the atomic weight of some elements like Be, In etc.
iii) $$(Ar , H_{2} ), (Co, Cl_{2}), (Te, F_{2})$$ are three inverted pairs.
iv) It is based on increasing order of atomic weights.

Which among the following elements has the largest atomic radii?

Upto which element, the law of octaves was applicable?

Number of short periods in Mendeleev's periodic table is :

The properties of _________ were predicted by Mendeleev before their isolation.

In Mendeleev's periodic table, gaps were left for the elements to be discovered later. Which of the following elements found a place in the periodic table later?

Mendeleev corrected the atomic weight of :