Question

31. A sheet of cardboard, a piece of muslin cloth and that of a transparent glass, all with same size and shape were placed at A one by one in the arrangement shown in figure.
Will the shadow be formed in each case? If yes, how will the shadow on the screen be different in each case? Give reasons for your answer

Answer 1

Explanation :

In order to make sure that the element having similar properties for sale in the same vertical column aur group mandali left some gaps in his periodic table. These gaps were left for subsequent in reason of elements not known at that time.