Hydrogen Hydrogen Hydrogen is a chemical element with symbol H and atomic number 1. With a standard atomic weight of , hydrogen is the lightest element on the periodic table. Its monatomic form (H) is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass. Non-remnant stars are mainly composed of hydrogen in the plasma state. The most common isotope of hydrogen, termed "protium" (name rarely used, symbol H), has one proton and no neutrons. The universal emergence of atomic hydrogen first occurred during the recombination epoch. At standard temperature and pressure, hydrogen is a colorless,
The Periodic Table (Basher book) different group of the periodic table (hydrogen, the alkali metals, the alkaline earth metals, the transition metals, the boron elements, the carbon elements, the nitrogen elements, the oxygen elements, the halogen elements, the noble gases, the lanthanides and actinides, and the transactinides). For every type of then known atom, Basher has created a "manga-esque" cartoon, and for many types of atoms, Dingle, a high-school chemistry teacher who also developed an award-winning chemistry website has written a couple paragraphs of facts to go with the cartoon. Dingle, who says that "[s]cience is a serious business", wanted in writing the book "to