Hydrogen is element 1 in the periodic table. It is a colorless, flammable gas that plays a big role in chemistry.
It is distinguished as the lightest and first element on the periodic table, plays a pivotal role in organic chemistry and is the most prevalent element in the cosmos, formed in the aftermath of the Big Bang. It constitutes 74% of the universe’s atomic mass and composes 90% of the sun. However, elemental hydrogen is scarcely found in Earth’s atmosphere, making up a mere 0.00005%, due to its high volatility and propensity to escape into space.
Despite its atmospheric scarcity, hydrogen is far from rare on Earth, where it is a fundamental component of countless compounds, including water. It is extracted through processes like electrolysis, which separates water into hydrogen and oxygen. The sun maintains its energy through the fusion of hydrogen into helium.
The discovery of hydrogen is credited to Henry Cavendish in 1766, who isolated it by reacting metals with acids. Shortly after, Antoine Lavoisier, a renowned chemist, developed electrolysis, demonstrating that water is a compound, not an element. Hydrogen’s applications are extensive and varied. Historically, it served as a fuel for zeppelins until the Hindenburg disaster in 1937, which highlighted its flammability. Today, research explores its potential in eco-friendly hydrogen vehicles, despite inherent risks compared to other types of cars.
Hydrogen has three isotopes, each with a unique name. Protium, the most abundant isotope, accounts for over 99.9% of hydrogen and consists of one proton and one electron. Deuterium, or “heavy hydrogen,” comprises about 0.01% and includes one neutron. It forms heavy water, which is slightly sweeter than regular water but should be consumed in moderation. Tritium, the radioactive isotope with a half-life of approximately 12 years, is rare in nature but can be produced artificially. While tritium-infused water should never be ingested, future advancements may harness the fusion of deuterium and tritium for energy production, a process requiring temperatures of several million degrees Celsius, akin to creating a synthetic sun. Although some experiments have been successful, the cost remains prohibitive for now.
Chemical Properties
Elemental Hydrogen
Elemental hydrogen usually exists as hydrogen gas(H2). Hydrogen gas can react with many nonmetals. For example, it combusts in oxygen and forms water, while burning it in chlorine will result in the formation of hydrogen chloride. Hydrogen burns with a light blue flame in oxygen.
Hydrogen Compounds
Hydrogen has the +1 oxidation state in most of its compounds. Some of the most famous compounds include water(H2O), methane(CH4), ammonia(NH3) and hydrogen peroxide(H2O2). All acids and nearly all complex organic molecules contain hydrogen. In a few compounds, like sodium hydride(NaH), the oxidation state of hydrogen is -1. These compounds are usually powerful reducing agents.
Applications
Hydrogen is used as an eco-friendly fuel, since the combustion of hydrogen gas only produces water. Liquid hydrogen is sometimes used as a rocket fuel. Hydrogen can also be used to produce ammonia, which can be further made into ammonium salts.