Cerium is a soft, ductile and silvery-white metal that tarnishes when exposed to air, and it is soft enough to be cut with a knife. Cerium is the second element in the lanthanide series. Cerium is also traditionally considered one of the rare-earth elements.
Protons and Neutrons in Cerium
Cerium is a chemical element with atomic number 58 which means there are 58 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 Cerium are 140, 142.
Main Isotopes of Cerium
Cerium occurs in 4 natural isotopes: 136Ce, 138Ce, 140Ce and 142Ce. 140Ce is the most common isotope, having a natural abundance of approximately 88%.
Cerium-136 is composed of 58 protons, 78 neutrons, and 58 electrons.
Cerium-138 is composed of 58 protons, 80 neutrons, and 58 electrons.
Cerium-140 is composed of 58 protons, 82 neutrons, and 58 electrons.
Cerium-142 is composed of 58 protons, 84 neutrons, and 58 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 Cerium is 58. 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 Cerium is [Xe] 4f1 5d1 6s2.
Possible oxidation states are +3,4.
Most Common Application of Cerium
Cerium is an important component of mischmetal alloy. Ferrocerium is a synthetic pyrophoric alloy that produces hot sparks that can reach temperatures of 3,000 °C (5,430 °F) when rapidly oxidized by the process of striking the rod, thereby fragmenting it and exposing those fragments to the oxygen in the air. A typical composition includes approximately 55% cerium, 25% lanthanum, and 15-18% neodymium with other rare earth metals following. The best-known use for this alloy is in ‘flints’ for cigarette lighters.
|Number of protons||58|
|Number of neutrons (typical isotopes)||140, 142|
|Number of electrons||58|
|Electron configuration||[Xe] 4f1 5d1 6s2|
Properties of other elements