Hydrogen is perhaps the most interesting of the elements in the universe, if not its simplest and most abundant one. Atoms of hydrogen represent about 75 percent of all the matter in the cosmos, and even the Earth’s crust contains more hydrogen than it does anything else. In fact, with the exception of Helium, all of the other elements in the universe have been formed from hydrogen atoms through a process which takes place in stars called fusion.
Hydrogen is an element with some very unusual and in some cases even exotic properties. It is also the most reactive of elements forming compounds with many other elements.
Chemical Properties
Hydrogen is the simplest element having an atomic number of 1 and its most common isotope has a mass number of 1 also. No other element boasts the same atomic number and mass number. Common hydrogen is unique in that it contains no neutrons, just a single proton in its nucleus and a single electron in orbit round it. Elemental hydrogen is bivalent, meaning that it can either accept or give up an electron in chemical reactions. Besides the common form of hydrogen, there are two isotopes, deuterium and tritium.
Physical Properties
Hydrogen is a gas which can be liquefied only under great pressure and at very cold temperatures. It is also a gas which has some unique properties when highly energized, forming a plasma which has a few unique properties of its own. In chemical reactions hydrogen can donate or accept an electron. Hydrogen even reacts with itself to form a diatomic molecule, and it is in this diatomic state that most hydrogen on earth is found. An example of this is water which consists of an oxygen atom and two hydrogen atoms. In the formation of compounds of hydrogen, substantial energy is dissipated. The combination of hydrogen and oxygen to form water is so vigorous that an enormous amount of energy is liberated and the reaction occurs explosively. This reaction is used to power rocket engines and it is also the primary source of energy in internal combustion engines. The octane rating of gasoline is essentially a measure of the amount of hydrogen it contains.
Hydrogen is lighter than air and in the past has been used in dirigibles and balloons, but its flammability presents a major drawback. Hydrogen is so light that the Earth’s gravity is not immense enough to hold on to it and when it rises to the top of the atmosphere it is swept away by the solar winds.
Biological Properties
Hydrogen has a very unusual property uncommon to any other element. The man whom James Watson referred to as the greatest chemist in the world, Linus Pauling, discovered this property in the 1940’s, setting the stage for the understanding of RNA, DNA, and life, that would unfold in the second half of the twentieth century. The property is called hydrogen bonding, and it is a property that is the underpinning of life itself. It is in essence the glue which binds the independent strands of DNA together to form the double helix structure. Hydrogen bonds are fragile, however, and therefore more easily broken then ionic or covalent bonds. It is this property which allows enzymes to separate DNA strands and make copies of them. This in essence is the process which drives all known forms of life in the universe.
Atomic Properties
Fusion of hydrogen atoms into helium is a process which takes place in the heart of stars and releases tremendous quantities of energy. Mankind would get a close up look at just how much energy is liberated in this nuclear reaction when the first hydrogen bomb was exploded in 1952, at Eniwetok atoll. The fireball produced was three miles in diameter and essentially vaporized everything within a 1 mile radius. That bomb was estimated to be equivalent to approximately 1 megaton of TNT. Today the United States have bombs with a capacity well in excess of 100 times that. Although none has ever been tested to establish its effects, these super bombs are expected to vaporize everything within 20 miles and incinerate everything within a 50 mile radius of ground zero. It is an awesome realization of the energy contained in the hydrogen atom.
