REED HOME Gryphon icon
Alumni Profiles
reed magazine logoSummer 2009

From the Archives

periodic table

Long shunted to the side, Hydrogen finally takes its rightful place at the head of the periodic table.

This misplacement of hydrogen at the head of the family of alkali metals has led to vivid bouts of unbridled imagination. After hydrogen was made conductive under high pressure, it was reported that “this is a testament to the inherent similarities of hydrogen and the other alkali metals.” Furthermore, it only needed “the use of additives, which would bond to the hydrogen molecules and atoms while they were under ultra high pressure…[and]…solid metallic hydrogen could be used to build lightweight automobiles.” The properties of these additives would, no doubt, require a new type of superglue that would have the most fantastic properties indeed!

Even when the search for metallic properties among the nonmetallic elements is unrestrained by earthbound reality, there is no reason to consider hydrogen any more metallic than a considerable number of other nonmetals. Boron, oxygen, sulfur, selenium, tellurium, and phosphorus have all been made conductive under pressure. Both boron and oxygen would seem to be better metallic candidates than hydrogen since both have already been pressured into superconductivity, while putting the squeeze on nitrogen has produced a semiconductor.

The metallization of hydrogen under pressure prompted inquires such as: “What is a metal?” and “When is a metal?” A more appropriate question might have been: Where does a nonmetal act like a metal? There are three likely places:

  1. In a sliver of space in an ultra-high-pressure laboratory.
  2. In a large gas bag, such as Jupiter.
  3. In the general neighborhood of a neutron star.
On such a star you might wish
more elements to squish.
But go there perhaps not,
lest you find yourself no larger than this •

Never Let Sleeping Dogmas Lie

The agreed-upon function of the periodic table has been to reflect a periodicity of physical and chemical properties of the elements with their increasing atomic number; however, there has been a surprising lack of any direct comparison of the chemistry of hydrogen and carbon, even though the relevant physical properties (ionization potential, electron affinity, electronegativity) place them in a close family relationship. The relationship of hydrogen to the carbon, silicon family of elements is clearly observable.

…[We omit Marsh’s lengthy demonstration showing that both hydrogen and carbon form strong covalent bonds, in contrast to the pathetic covalent bonding power of the alkali metals.]

There are those who have relied on chemists, for better or for worse, to provide them with a coherent arrangement of the elements in such a way as to disclose the ties that bind within their physically and chemically related families. There should be no more excuses for such shoddy treatment of hydrogen as to deny its chemical lineage. So, now we are ready for a new family photo op, not provided by the authority of any person or committee. As with all entries into the scientific lexicon, it comes courtesy of publicly available, sensible phenomena with their attendant logical consequences. Only three rows of the table are needed to illustrate this long overdue correction. Slide hydrogen over to the middle of the row above carbon (see the revised periodic table below). Notice how well the relevant physical properties display the genetic origins of the chemistry in each family group. Say “Chemistry” everyone. Click!

Editor’s Note: The legendary Marsh Cronyn ’40 taught chemistry at Reed from 1952 to 1989 and died in 2007. This article is condensed and adapted from the Journal of Chemical Education, August 2003. Click here for the complete text of Marsh's article.

reed magazine logoSummer 2009