What are non-renewable resources of energy? Give two examples of such resources.
The energy sources that are consumed at a rate faster than the rate at which they are replenished are called Non-renewable resources.
E.g., Coal and petroleum.
On the basis of electronic configuration, how will you identify the first and the last element of a period?
(i) How do you calculate the possible valency of an element from the electronic configuration of its atoms?
(ii) Calculate the valency of element X whose atomic number is 9.
Write any two differences between binary fission and multiple fission in a tabular form as observed in cells of organisms.
