-Hydrogen makes up about 75% of the mass of the universe. it is found in the sun and most stars -its is the lightest and simplest element on the periodic A-1 M-1 A- atomic number m- atomic mass p-1 A- 1 p- protons a- atomic number E-1 N- 0 e- electrons n- neutrons -It is odorless, colorless, and tasteless. -hydrogen is 14 times lighter than the air we breath -Hydrogen is from the greek word hydro -hydrogen can augment or replace most other types of combustion fuel -non-toxic & non corrosive -it is flammable -normal boiling point of- 253°C (- 423°F)