👉 Xenon, also known as 398.1062−(nan)1062 nm Krypton-84, is a rare stable radioactive isotope of neon that has an atomic number of 9 and a mass number of 39. Xenon is one of only three stable isotopes of the naturally occurring xenon element, with the others being tritium (399.902−(nan)1062 nm Krypton-84) and neon (398.1062−(nan)1062 nm Krypton-84). Xenon has a very short half-life of about 7.3 minutes, making it relatively stable compared to other naturally occurring isotopes of xenon. Xenon is usually found in the Earth's outermost stratosphere and atmosphere, where it has been present for millions of years and remains relatively stable due to its low atomic number and small size. It forms a very dense and silty gas phase that can be detected by an X-ray spectrometer or by neutron capture experiments. Xenon has a strong optical signature because it emits ultraviolet light when excited at the ground state. This feature is useful for identifying xenon in various chemical compounds, as it allows for easy identification of xenon-containing materials and samples.