Mercury, also known as quicksilver or hydrargyrum, is a chemical element. Sources, facts, uses, scarcity (SRI), podcasts, alchemical symbols, videos and images. Its atomic mass is 200.59. Hydrogen is a chemical element with atomic number 1 which means there are 1 protons and 1 electrons in the atomic structure.The chemical symbol for Hydrogen is H. With a standard atomic weight of circa 1.008, hydrogen is the lightest element on the periodic table. Element Mercury (Hg), Group 12, Atomic Number 80, d-block, Mass 200.592. Its symbol on the periodic table is Hg, and its atomic number is 80. The name mercury originated in 6th-century alchemy, in which the symbol of the planet was used to represent the metal; the chemical symbol Hg derives from the Latin hydrargyrum, “liquid silver.” Although its toxicity was recognized at an early date, its main application was for medical purposes. Its monatomic form (H) is the most abundant chemical substance in the Universe, constituting roughly 75% of all baryonic mass. The symbol Hg stands for its Latinized Greek name hydrargyrum, meaning watery or liquid silver.