Hydrogen is a chemical element having the atomic number 1 and is given in the symbol H. An atom of hydrogen is composed of one proton and no neutrons in the nucleus; it has one electron in its 1s orbital. The electron configuration of hydrogen is given as 1s1. Hydrogen is an s block element in the periodic table. The atomic weight of hydrogen is 1.00794 amu.
At room temperature and pressure, hydrogen exist as a diatomic gaseous molecule. It is a colorless and odorless gas. The melting point of hydrogen is about -259oC. The boiling point comes around -252oC. Hydrogen has three oxidation states. They are -1, 0 and +1. When hydrogen is attached to a metal atom, it has -1 oxidation state.
There are three major isotopes of hydrogen: Protium, Deuterium, and tritium. Protium is the most abundant isotope and has an abundance of 99%. Therefore, when we generally talk about hydrogen, we are talking about Protium. Deuterium is also a stable isotope but is less abundant. It has a neutron in its nucleus whereas Protium does not. Tritium is a radioactive isotope. Furthermore, there are many other isotopes that are not stable, and are highly radioactive.
There are many applications of hydrogen gas. Large quantities of hydrogen are used in the processing of fossil fuels. Hydrogen gas is also used in the production of ammonia. Moreover, hydrogen is used as a coolant in power plants as well.