Encyclopedia

hydrogen

hydrogen (hī'drujun) [key][Gr.,=water forming], gaseous chemical element; symbol H; at. no. 1; at. wt. 1.00794; m.p. -259.14°C; b.p. -252.87°C; density 0.08988 grams per liter at STP; valence usually +1.

Sections in this article:

The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2007, Columbia University Press. All rights reserved.

More on hydrogen from Fact Monster:

  • tritium - tritium tritium , radioactive isotope of hydrogen with mass number 3. The tritium nucleus, called a ...
  • hydrogenation - hydrogenation hydrogenation , chemical reaction of a substance with molecular hydrogen, usually in ...
  • HYDROGEN - You cannot see, taste, or smell hydrogen, yet this element makes up over 90 per cent of matter. The Sun and stars are made of hydrogen gas. On Earth,

See more Encyclopedia articles on: Compounds and Elements