|Class 11 Chemistry Hydrogen||Introduction|
On the earth Hydrogen exists as H2 molecule (dihydrogen). It constitutes to 10 % mass of universe. Hydrogen exit in many substances like carbohydrates, hydrocarbons etc. It is actually 3rd most abundant element
As you know, isotopes differ in number of neutrons .So, accordingly Protium has no neutron, Deuterium has 1 and Tritium has 2 neutrons. It is 1st element in Periodic table. Its position is anomalous as it resembles alkali metal and halogen.