1) Hydrogen is the first element in the periodic table. 2) It is the lightest element known. 3) It atomic form exists only at high temperature. 4) It exist as a diatomic molecule i.e. H2 .That is why it is also called dihydrogen. 5) It was discovered by Henry Cavendish in 1766. 6) Its electronic configuration is 1s1 Unique position of Hydrogen in periodic … [Read more...] about Position of Hydrogen