![]() When hydrogen is consumed in fuel cells, the only emission at the point of use is water vapour. Hydrogen can be deployed as an energy source in fuel cells to produce electricity, or via combustion to generate heat. Most hydrogen is used near the site of its production, the two largest uses being fossil fuel processing (e.g., hydrocracking) and ammonia production. A small percentage is also produced using more energy-intensive methods such as the electrolysis of water. Industrial production is mainly from steam reforming of natural gas, oil reforming, or coal gasification. In 1766–1781, Henry Cavendish was the first to recognize that hydrogen gas was a discrete substance and that it produces water when burned, the property for which it was later named: in Greek, hydrogen means "water-former". Hydrogen gas was first artificially produced in the early 16th century by the reaction of acids on metals. Because hydrogen is the only neutral atom for which the Schrödinger equation can be solved analytically, the study of its energetics and chemical bonding has played a key role in the development of quantum mechanics. The H + cation is simply a proton (symbol p) but its behavior in aqueous solutions and in ionic compounds involves screening of its electric charge by nearby polar molecules or anions. In ionic compounds, hydrogen can take the form of a negative charge (i.e., anion) where it is known as a hydride, or as a positively charged (i.e., cation) species denoted by the symbol H +. Hydrogen plays a particularly important role in acid–base reactions because these reactions usually involve the exchange of protons between soluble molecules. Hydrogen is nonmetallic (except when it becomes metallic at extremely high pressures) and readily forms a single covalent bond with most nonmetallic elements, forming compounds such as water and nearly all organic compounds. ![]() The emergence of neutral hydrogen atoms throughout the universe occurred about 370,000 years later during the recombination epoch, when the plasma had cooled enough for electrons to remain bound to protons. In the early universe, the formation of protons, the nuclei of hydrogen, occurred during the first second after the Big Bang. If atoms are made up mostly of "empty space," what is in that empty space? Steve Gagnon, Science Education Specialist ( Other answers by Steve Gagnon) While I wouldn't want something that big landing on my head, it's tiny compared to the size of the earth. Put another way, if a hydrogen atom were the size of the earth, the proton at its center would be about 200 meters (600 feet) across. If 0.0000000000004% of a hydrogen atom is full, then the rest of it must be empty:Ī hydrogen atom is about 99.9999999999996% empty space. Percent Full = 100 × (Volume Filled / Total Volume) We need to do a little more math to find out how much of a hydrogen atom is empty space: 84 × 10 -15 meters, giving them a volume of about 2.5 × 10 -45 cubic meters. How big is the proton at the center of a hydrogen atom? Recent studies indicate that protons have a radius of about. That means that a hydrogen atom has a volume of about 6.2 × 10 -31 cubic meters. ![]() How big is a hydrogen atom? The radius of a hydrogen atom is known as the Bohr Radius, which is equal to. Of course, this diagram isn't drawn to scale.Ī hydrogen atom is made from a single proton that's circled by a single electron. Let's take a look at an atom of hydrogen to see how empty it really is. ![]()
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