Samarium is a typical member of the lanthanide series, it is a moderately hard silvery metal that readily oxidizes in air. The name samarium is after the mineral samarskite from which it was isolated. Although classified as a rare earth element, samarium is the 40th most abundant element in the Earth’s crust and is more common than such metals as tin. In nuclear industry, especially natural and artificial samarium 149 has an important impact on the operation of a nuclear reactor. Samarium 149 has a very large neutron capture cross-section (about 42,000 barns). Since natural samarium contains about 14% of 149Sm, it can be used as an absorbing material in control rods.
Electron Affinity – Samarium
Electron affinity of Samarium is 50 kJ/mol.
In chemistry and atomic physics, the electron affinity of an atom or molecule is defined as:
the change in energy (in kJ/mole) of a neutral atom or molecule (in the gaseous phase) when an electron is added to the atom to form a negative ion.
X + e– → X– + energy Affinity = – ∆H
In other words, it can be expressed as the neutral atom’s likelihood of gaining an electron. Note that, ionization energies measure the tendency of a neutral atom to resist the loss of electrons. Electron affinities are more difficult to measure than ionization energies.
Electronegativity of Samarium
Electronegativity of Samarium is 1.17.
Electronegativity, symbol χ, is a chemical property that describes the tendency of an atom to attract electrons towards this atom. For this purposes, a dimensionless quantity the Pauling scale, symbol χ, is the most commonly used.
The electronegativity of Samarium is: χ = 1.17
First Ionization Energy of Samarium
First Ionization Energy of Samarium is 5.6437 eV.
Ionization energy, also called ionization potential, is the energy necessary to remove an electron from the neutral atom.
X + energy → X+ + e−
where X is any atom or molecule capable of being ionized, X+ is that atom or molecule with an electron removed (positive ion), and e− is the removed electron.
A Samarium atom, for example, requires the following ionization energy to remove the outermost electron.
Sm + IE → Sm+ + e− IE = 5.6437 eV
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 Samarium is 62. 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 Samarium is [Xe] 4f6 6s2.
Possible oxidation states are +2,3.
|Number of electrons||62|
|Electron configuration||[Xe] 4f6 6s2|
|Electron affinity [kJ/mol]||50|
|Electronegativity [Pauling scale]||1.17|
|First ionization energy [eV]||5.6437|
Properties of other elements