1Are all the elements made up of the same type of atoms?
2Are the physical and chemical properties of one element similar to those of other elements?
3How has classification made the study of elements easier?
4What is classification of elements?
5Why are the elements classified?
6What is the basis of classification of elements?
7Do all metals have the same properties?
8Is there any relation between the atomic structure of elements and their properties? How are the properties of elements related to their atomic structures?
9Among oxygen, iron, silver, sodium, chlorine, aluminium, carbon, sulphur and nitrogen, which are metals and which are non-metals?
10What is a periodic table?
11State Mendeleev's periodic law and explain what it means.
12What are groups and periods in a periodic table?
13How many elements have been discovered so far? How many of them are natural and how many artificial?
14Why are lithium, sodium and potassium placed in the same group?
15Why is the periodic table called periodic?