Xenon is a colorless, dense, odorless noble gas found in the Earth’s atmosphere in trace amounts. Although generally unreactive, xenon can undergo a few chemical reactions. Xenon was first discovered in 1898 by the Scottish chemist William Ramsay and English chemist Morris Travers. The name xenon for this gas comes from the Greek word ξένον [xenon], neuter singular form of ξένος [xenos], meaning ‘foreign(er)’, ‘strange(r)’, or ‘guest’. In nuclear industry, especially artificial xenon 135 has a tremendous impact on the operation of a nuclear reactor. For physicists and for reactor operators, it is important to understand the mechanisms that produce and remove xenon from the reactor to predict how the reactor will respond following changes in power level.
Protons and Neutrons in Xenon
Xenon is a chemical element with atomic number 54 which means there are 54 protons in its nucleus. Total number of protons in the nucleus is called the atomic number of the atom and is given the symbol Z. The total electrical charge of the nucleus is therefore +Ze, where e (elementary charge) equals to 1,602 x 10-19 coulombs.
The total number of neutrons in the nucleus of an atom is called the neutron number of the atom and is given the symbol N. Neutron number plus atomic number equals atomic mass number: N+Z=A. The difference between the neutron number and the atomic number is known as the neutron excess: D = N – Z = A – 2Z.
For stable elements, there is usually a variety of stable isotopes. Isotopes are nuclides that have the same atomic number and are therefore the same element, but differ in the number of neutrons. Mass numbers of typical isotopes of Xenon are 128-135.
Main Isotopes of Xenon
Xenon occurs in 9 natural isotopes: 124Xe, 126Xe, 128Xe, 129Xe, 130Xe, 131Xe, 132Xe, 134Xe and 136Xe. 124Xe, 126Xe, 134Xe and 136Xe are very slightly radioactive. 132Xe is the most common isotope, having a natural abundance of approximately 26.9%.
Xenon-124 is composed of 54 protons, 70 neutrons, and 54 electrons.
Xenon-126 is composed of 54 protons, 72 neutrons, and 54 electrons.
Xenon-128 is composed of 54 protons, 74 neutrons, and 54 electrons.
Xenon-129 is composed of 54 protons, 75 neutrons, and 54 electrons.
Xenon-130 is composed of 54 protons, 76 neutrons, and 54 electrons.
Xenon-131 is composed of 54 protons, 77 neutrons, and 54 electrons.
Xenon-132 is composed of 54 protons, 78 neutrons, and 54 electrons.
Xenon-134 is composed of 54 protons, 80 neutrons, and 54 electrons.
Xenon-136 is composed of 54 protons, 82 neutrons, and 54 electrons.
Electrons and Electron Configuration
The number of electrons in an electrically-neutral atom is the same as the number of protons in the nucleus. Therefore, the number of electrons in neutral atom of Xenon is 54. Each electron is influenced by the electric fields produced by the positive nuclear charge and the other (Z – 1) negative electrons in the atom.
Since the number of electrons and their arrangement are responsible for the chemical behavior of atoms, the atomic number identifies the various chemical elements. The configuration of these electrons follows from the principles of quantum mechanics. The number of electrons in each element’s electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior. In the periodic table, the elements are listed in order of increasing atomic number Z.
Electron configuration of Xenon is [Kr] 4d10 5s2 5p6.
Possible oxidation states are 0.
Most Common Application of Xenon
Xenon is used in light-emitting devices called xenon flash lamps, used in photographic flashes and stroboscopic lamps. Although generally unreactive, xenon can undergo a few chemical reactions such as the formation of xenon hexafluoroplatinate, the first noble gas compound to be synthesized.
|Number of protons||54|
|Number of neutrons (typical isotopes)||128-135|
|Number of electrons||54|
|Electron configuration||[Kr] 4d10 5s2 5p6|
Properties of other elements