Krypton, a colorless and odorless gas with the atomic number 36 (Kr), belongs to the family of elements known as the noble gases. Like its counterparts in Group 18 of the periodic table, it is characterized by extremely low chemical reactivity and inherent stability. The name holds historical significance that relates directly to the circumstances of its initial detection in the late 19th century. The story behind its naming reflects the unique challenge scientists faced in separating it from common atmospheric components.
The Context of Its Discovery
The existence of Krypton was confirmed in 1898, marking a significant moment in the study of atmospheric gases. Scientists focused on the minute portions of air remaining after the most abundant components had been physically removed. They began with a large volume of air that had been liquefied by cooling it to extremely low temperatures.
This separation process relied on the difference in boiling points between the various gases present in the liquid air. As the sample was gradually allowed to warm, the vast majority evaporated first, including nitrogen and oxygen, which constitute the bulk of the air. The previously identified noble gas, argon, also boiled away before the new substance.
This left behind a tiny, non-volatile residue that was subjected to analysis using spectroscopy. The residue represented an incredibly small fraction of the original sample, revealing that Krypton makes up only about one part per million of the Earth’s atmosphere. Its presence as a trace substance, hidden within the last remnants of the liquefied air, set the stage for its eventual designation.
The Meaning of the Name
The designation of this elusive element as “Krypton” was a deliberate choice reflecting the difficulty of its isolation. The name is derived from the ancient Greek word kryptos (κρυπτός), which translates as “the hidden one” or “secret.”
The link between the word and the element is clear. Scientists had to process a massive amount of atmospheric gas to yield just a tiny volume of the new substance. The element was literally hidden within the atmospheric mixture, stubbornly resisting detection through conventional means due to its extremely low natural abundance.
The discovery of an element that existed in such minute and concealed quantities naturally inspired the use of the Greek term for “hidden” to identify it permanently. The chosen name summarizes the element’s status as a gas that remained undetected for so long, only to be found in the final portion of the air sample.