Comparing ⁴He with ²H₂ – An Atom with a Molecule?
The title of this article may seem a bit strange. How do we begin comparing a helium-4 atom with a molecule of deuterium hydrogen? It may become more apparent if we examine illustrations of the two species. Note the similarities and the differences. If you do, comparing 4He with 2H₂ should not seem so strange. Helium-4 Helium is element number two in the periodic table. This means helium has an atomic number of two—it has two protons. Protons are positively charged. Now an atom is neutral, thus electrical neutrality dictates a helium atom also has two electrons. The only variable is the number of neutrons. Helium-4 (sometimes written 4He) is a very stable form of helium and has two neutrons. Deuterium or Heavy Hydrogen Atomic hydrogen (symbol H) consists primarily…