kon Itosen (toki Kanse: hydrogène) (toki Lasina: hydrogenium) li ijo nasin pi wan Atomo. ona li jo e sitelen lili H e nanpa Atomo 1. kulupu Molekula Itosen li jo e wan Atomo nanpa tu. mute la, ona li nasin pi wan Atomo nanpa wan lon ali. nanpa 75% pi ijo lon ali li ijo Itosen.
kon Itosen li kama telo lon lete nanpa −252.879 °C ona li kama kiwen lon lete nanpa −259.16 °C.