Periodic Classi...

Atomic wt. of P is 31 and Sb is 120. What will be the atomic wt. of As, as per Dobernier triad rule?

How does number of valence electrons vary on moving from left to right In the first period of a periodic table?

Which of the following elements is a metalloid?

If A, B and C are the three elements of Dobereiner's triad and atomic weights of A and B are 7 and 15 respectively, then the atomic weight of C is :

Which of the following is the correct match?
(a) Eka silicon - $$\text{Ge}$$
(b) Eka aluminum - $$\text{Ga}$$
(c) Eka manganese - $$\text{Tc}$$
(d) Eka boron - $$\text{Sc}$$

Who was the first to classify the elements into metals and non-metals?

Which of the following has maximum non-metallic character?

Which of the following pairs of elements does not follow the Law of Octaves?

According to Mendleev's periodic law which properties of the elements are the periodic function of their atomic masses?

On moving from top to bottom in a group in the periodic table, valency: