Copy and complete the following sentences choosing the correct word or words from those given in brackets at the end of each sentence :

The similarities in the properties of a group of elements is because they have the same …………… [electronic configurations, number of outer electrons, atomic numbers.]

What is meant by a Group in the Periodic Table.

What are elements. Give a reason why elements need to be properly classified.

How did the early chemists classify elements. Why was this basis of classification discarded for future classification of elements.