Barium is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. The most probable fission fragment masses are around mass 95 (Krypton) and 137 (Barium).
Protons and Neutrons in Barium
Barium is a chemical element with atomic number 56 which means there are 56 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 Barium are 134-138.
Main Isotopes of Barium
Barium occurs in 6 natural isotopes: 132Ba, 134Ba, 135Ba, 136Ba, 137Ba and 138Ba. 138Ba is the most common isotope, having a natural abundance of approximately 71%.
Barium-132 is composed of 56 protons, 76 neutrons, and 56 electrons.
Barium-134 is composed of 56 protons, 78 neutrons, and 56 electrons.
Barium-135 is composed of 56 protons, 79 neutrons, and 56 electrons.
Barium-136 is composed of 56 protons, 80 neutrons, and 56 electrons.
Barium-137 is composed of 56 protons, 81 neutrons, and 56 electrons.
Barium-138 is composed of 56 protons, 82 neutrons, and 56 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 Barium is 56. 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 Barium is [Xe] 6s2.
Possible oxidation states are +2.
Most Common Compound of Barium
Barium is a key element in the production of ceramic superconductors. Lanthanum barium copper oxide, or LBCO, was discovered in 1986 and was the first high temperature superconductor. An yttrium–barium cuprate, YBa2Cu3O7−x (or Y123), was the first superconductor found above liquid nitrogen boiling point. There are two atoms of Barium for each atom of Yttrium.
|Number of protons||56|
|Number of neutrons (typical isotopes)||134-138|
|Number of electrons||56|
|Electron configuration||[Xe] 6s2|
Properties of other elements