A is a reddish brown metal, which combines with O₂ at < 1370 K gives B, a black coloured compound. At a temperature > 1370 K, A gives C which is red in colour. Find A, B and C with reaction.

A is a silvery white metal. A combines with O₂ to form B at 800^oC, the alloy of A is used in making the aircraft. Find A and B.

What is rust? (or) How is rust formed? Give the equation for formation of rust.

State two conditions necessary for rusting of iron.

Why are elements of group 18 unreactive?

What is the significance of modem periodic table?

Name the periodic properties and why are they called so?

The value of d (C-C) distance is experimentally found to be 1.54 A^o. Find its covalent radius.

Atomic radii decreases as we more from left to right of periodic table. Justify your answer

Define the term Ionic Radii.

"Noble gases have zero electron affinity". Say True and False and Justify your answer.

Ionisation energy decreases down the group in periodic table. Give reason.

What is flux? Give example.

Look at the diagram and predict the ore which is being concentrated?

Name a metal that can be cut with a knife.