text: The elements that occur on Earth only in traces are listed below. 
  Isotopes of other elements (not exhaustive):
  *Tritium
  *Beryllium-7
  *Beryllium-10
  *Carbon-14
  *Fluorine-18
  *Sodium-22
  *Sodium-24
  *Magnesium-28
  *Silicon-31
  *Silicon-32
  *Phosphorus-32
  *Sulfur-35
  *Sulfur-38
  *Chlorine-34m
  *Chlorine-36
  *Chlorine-38
  *Chlorine-39
  *Argon-39
  *Argon-42
  *Calcium-41
  *Iron-60
  *Nickel-59
  *Selenium-79
  *Krypton-81
  *Strontium-90