Why Hydrogen is known as Rogue element?
HYDROGEN THE ROGUE ELEMENT Hydrogen has similarities with elements of both (periodic table) Group1 Alkali metals(Li,Na,K etc) and elements of the Group that is Group 17 Halogens (F,Cl,Br etc). Hence, Mendeleev faced difficulties in finding a particular position for Hydrogen.So,he named Hydrogen as Rogue element. (1)Similarities with Alkali metals: (a)Hydrogen forms cation like alkali metals . H - e- = H+ Na - e- = Na+ (b)The valency of Hydrogen is 1 like Alkali metals. (2)Similarities of Hydrogen with Halogens: (a)Hydrogen is non-metal di atomic like Halogens. ex- H2, F2 , Cl2 , Br2 etc. (b)Hydrogen can gain 1 electron to make unit negatively charged anions like Halogens. Cl + e- = Cl- H + e- = H- . If you are interested in Biology then click on this: interesting fact on Biology