Represent with the help of a simple chart how matter is classified into pure or impure substances & further into elements, compounds & mixtures, with elements further segmented.

Define the terms elements, compounds & mixtures with a view to show their basic difference.

'The modern periodic table consists of elements arranged according to their increasing atomic numbers'. With reference to elements with atomic numbers 1 to 20 only in the periodic table — differentiate them into — metallic elements, metalloids, non-metals & noble gases.

Elements are broadly classified into metals & non-metals. State six general differences in physical properties of metals & non-metals. State two metals & two non-metals which contradict with the general physical properties — giving reasons. State one difference in property between metalloids & noble gases.