Hydrogen is the first element in the periodic table and the first element in Group 1 of the table. It has an atomic number of 1, an atomic mass of 1.00794, and a chemical symbol of H.

Properties

Hydrogen is a colorless, odorless, tasteless gas with a density of 0.08999 grams per liter. By comparison, a liter of air weighs 1.29 grams, 14 times as much as a liter of hydrogen. Hydrogen's boiling point is -422.99°F (-252.77°C) and its freezing point is -434.6°F (-259.2°C). It is slightly soluble in water, alcohol, and a few other common liquids.

Hydrogen is relatively inactive at room temperature, but at elevated temperatures it reacts vigorously with many elements, include oxygen, sulfur, phosphorus, and the halogens. The reaction between hydrogen and oxygen results in the formation of water: 2H₂ + O₂ 2H₂O.

Occurrence and Extraction

Hydrogen is the most abundant element...