Name a non-metal which is extremely hard.

63 Name a non-metal which conducts electricity. 63 Name a non-metal having luster (shining surface). 63 How do non-metals react with oxygen? Explain with an example. Give equation of the reaction involved.

What is the nature of the product formed? How will you demonstrate it?

64 What is meant by the reactivity series of metals? Arrange the following metals in an increasing order of their reactivity towards water:

Zinc, Iron, Magnesium, Sodium