Molar Ionization Energies of the Elements

The list of the molar ionization energies of the elements gives the ionization energy necessary for each of the ionizations of the listed atoms. The first ionization concerns the neutral atom, while the others give the energy values necessary to remove each additional electron.

The values are expressed in kilojoules per mole (kJ⋅mol⁻¹).

Data for rutherfordium or any element with a higher atomic number are theoretical predictions.

The ionization potential or molar ionization energies of an atom or a molecule is the energy necessary to tear an electron from it. More generally, the …th ionization energy is the energy required to tear off the …th electron after the first n-1 electrons have been stripped. In physical chemistry, the concept of ionization energy is the reverse of that of electronic affinity, that is to say of its propensity to give up or on the contrary to retain an electron.

General

Ionization energy is expressed in eV or Joule or kiloJoule / mole (kJ / mole). 1 electron-Volt is very close to 100 kJ / mole. It is a magnitude which is always positive, which means that it is always necessary to provide energy to an atom to snatch one (or more) electrons from it. The ionization energy varies according to the atom or the molecule considered, as well as its state of ionization.

You can ionize an atom with more than one electron in several steps. For example, a boron atom has five electrons: two in an inner shell (1s2) and three in the valence shell (2s2 and 2p1). The ionization energy of order n is the energy necessary to successively separate n electrons from the atom. The energy of first ionization varies a lot between atoms. Ionization energy rises along one row of the Periodic Table of Elements then sharply decreases when moving to another row.

The torn electron that is considered in the concept of ionization energy comes from the valence layer. But it can happen that an electron from the deep layers of the atom is torn off without the electrons from the superficial layers having been torn off beforehand; in this case the electrons then reorganize themselves, giving rise to radiation (X-ray fluorescence).

Numerical values ​​of ionization energies

Generally speaking, ionization energies decrease along a column of the Periodic Table of the Elements and increase from left to right along a row of the table. The ionization energy shows a strong anticorrelation with the atomic radius. The successive ionization energies of a given element gradually increase, as can be seen in the table below. The increase is particularly strong when after the complete exhaustion of a layer of atomic orbital, one passes to a new layer. This is because when all the electrons in an orbital have been extracted, the next ionization energy will be to extract an electron from an orbital closer to the nucleus, where the electrostatic force that binds the electron to the nucleus is more intense.

Ionization energy in quantum mechanics

Bohr’s model does not quite conform to the theory of quantum mechanics, better described by the Schrödinger Model according to which the location of the electron is described not deterministically, but as a “cloud” of locations with a certain probability of being more or less close to the nucleus. This more rigorous approach is also a more complicated one, but we can give some avenues to approach it: The cloud corresponds to a wave function or, more precisely to a linear combination of Slater’s determinants, that is to say , according to the Pauli Exclusion Principle, antisymmetric products of Atomic Orbital or Molecular Orbital. This linear combination is an interacting development of configurations of the electronic wave function.

In the general case, to calculate the nth ionization energy, it is necessary to subtract the energy of a system of Z – n + 1 electrons from a system of Z – n electrons. The calculation of these energies is not simple, but it is a fairly classic problem of what is called computational chemistry, that is, the study of chemistry by digital scanning. As a first approximation, the ionization energy can be deduced from Koopmans theorem

1st–10th ionisation energies – Molar Ionization Energies of the Elements

11th–20th Molar Ionization Energies of the Elements

21st–30th Molar Ionization Energies of the Elements

Periodic Table of Elements | Complete List of Chemical Elements by Group, Name, Symbol, Color and Type

Sources: PinterPandai, Chemicool, Live Science, Royal Society of Chemistry

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