Hydrogen: An A–Z Comprehensive Encyclopedia
A. Atomic Structures And Basic Properties
Hydrogen, the simplest element in the periodic table, has an atomic number of 1 and an atomic mass of approximately 1.008 u. Its electronic configuration is 1s¹, making it highly reactive and versatile in chemical bonding. Hydrogen exists in three isotopic forms: protium, which is the most abundant with no neutrons; deuterium, containing one neutron and used in heavy water and nuclear reactors; and tritium, a radioactive isotope with two neutrons, utilized in fusion reactions and luminous devices. Comprising about 75% of the elemental mass of the universe, hydrogen is the primary fuel of stars. On Earth, free hydrogen is rare due to its low molecular weight, but it is abundant in compounds such as water and hydrocarbons.
B. Bonding and Chemical Behaviour
Hydrogen exhibits multiple bonding behaviours, forming covalent bonds with non-metals such as in water (H₂O), methane (CH₄), and ammonia (NH₃), and ionic hydrides with metals like sodium hydride (NaH) or calcium hydride (CaH₂). Its ability to participate in hydrogen bonding is fundamental to the physical properties of water and the stability of biological macromolecules such as proteins and DNA. This weak but significant intermolecular force contributes to phenomena like water’s high boiling point, surface tension, and liquid state at room temperature, demonstrating hydrogen’s crucial role in both chemistry and life..
C. Compounds of hydrogen
Hydrogen forms a wide variety of compounds, spanning inorganic, organic, and metallic domains. Inorganic hydrogen compounds include hydrogen halides such as HCl, ammonia (NH₃), and water (H₂O). Organic compounds feature hydrocarbons and biomolecules like carbohydrates, lipids, and proteins, which rely on hydrogen for structural stability. Metal hydrides are studied as hydrogen storage materials, while hydrogen also forms the basis of mineral acids such as H₂SO₄ and HNO₃. Across industries and biological systems, hydrogen’s compounds are central to energy production, agriculture, and chemical synthesis.