The chemical element Krypton is a naturally occurring component of the Earth’s atmosphere, recognized for its unique properties and specialized industrial applications. The internationally accepted symbol for Krypton is Kr. This two-letter designation represents the element with the atomic number 36.
Identifying the Symbol and Naming
The symbol Kr is a direct abbreviation of the element’s name, Krypton, following the standard conventions set by the International Union of Pure and Applied Chemistry (IUPAC). All chemical elements are assigned a unique one- or two-letter symbol. Krypton’s atomic number, 36, indicates that every neutral atom of this element contains 36 protons in its nucleus.
The name Krypton originates from the Greek word kryptos, which translates to “the hidden one” or “concealed.” British chemists Sir William Ramsay and Morris W. Travers discovered the element in 1898 from the residue of evaporated liquid air. This discovery reflected its rare and previously undetected nature in the atmosphere.
Classification and Basic Properties
Krypton belongs to Group 18 of the periodic table, classifying it as one of the noble gases. This means Krypton is colorless, odorless, and exists as a monatomic gas, where atoms do not readily bond to form molecules. A defining feature of noble gases is their high degree of chemical inertness, which stems from having a complete outer electron shell containing eight valence electrons.
This full valence shell configuration gives Krypton exceptional stability, making it highly unreactive under normal conditions. It is significantly denser than air, which contributes to some of its practical uses. Krypton is present in the Earth’s atmosphere only in trace amounts, making up roughly one part per million by volume. Extracting this rare gas involves fractional distillation of cooled liquid air.
Practical Applications of Krypton
Krypton’s distinctive properties, particularly its high atomic mass and spectral emission lines, make it valuable in several technological applications. One of its most common uses is in specialized lighting, where it is employed as a filling gas in high-performance incandescent bulbs and fluorescent lamps. When electrically charged, the gas emits a bright, white light, desirable for applications like airport runway lights and high-speed photographic flash lamps.
The inert nature and low thermal conductivity of Krypton also make it an effective insulating medium. It is often sealed between the panes of double-glazed windows to create energy-efficient insulation, providing better thermal performance than the more commonly used Argon gas. Krypton is also a component in certain laser systems. The Krypton Fluoride (KrF) excimer laser utilizes a compound of the gas to produce high-energy ultraviolet light, a technology crucial in semiconductor manufacturing for precision photolithography.