Ionization energy

Regular energy trends of (E_i) in front of the atomic number: tengase in account that "in" each of the seven branches the E_i (color circles) of an element begins in a "minimum" for the first column of the periodic table (alkaline metals), and progresses to a "maximum" for the last column (noble gases) indicated by vertical lines, and which also serve as lines that divide the 7 periods. Note that the maximum ionization energy for each row decreases as it moves from row 1 to row 7 in a given column, due to the growing distance of the outer layer of electrons from the core as the inner layers are added.

The ionization energy (E_i) is the energy needed to separate an electron in its ground state from an atom of an element in a gaseous state.

A(g)+Ei→ → A+(g)+e− − {displaystyle mathrm {A(g)} +E_{rm {i}}to mathrm {A^{+}(g) +e^{-}} }.

Being A(g){displaystyle {rm {A(g)}}}} atoms in a gaseous state of a certain chemical element; Ei{displaystyle E_{rm {i}}}, ionization energy and e− − {displaystyle {rm {e^{e}}}} an electron.

This energy corresponds to the first ionization. The second ionization energy represents the energy needed to remove the second electron; This second ionization energy is always greater than the first, since the volume of a positive ion is less than that of the atom and the attractive electrostatic force supported by this second electron is greater in the positive ion than in the atom, since it is conserved. the same nuclear charge.

Ionization energy is expressed in electron volts, joules, or kilojoules per mole (kJ/mol).

1 eV = 1.6 × 10^-19 C × 1 V = 1.6 × 10^-19 J

In the elements of the same family or group, the ionization energy decreases as the atomic number increases, that is, from top to bottom.

However, the increase is not continuous, since in the case of beryllium higher values are obtained than what could be expected by comparison with the other elements of the same period. This increase is due to the stability of the s² and s²p³ configurations, respectively.

The highest ionization energy corresponds to the noble gases, since their electronic configuration is the most stable, and therefore more energy will have to be provided to remove the electrons.

Ionization potential

The ionization potential (P_I) is the minimum energy required to separate an electron from a specific atom or molecule at such a distance that there is no electrostatic interaction between the ion and the electron. Initially it was defined as the minimum potential necessary for an electron to leave an atom that is ionized. The ionization potential was measured in volts. Today, however, it is measured in electronvolts (although it is not an SI unit) although it is accepted in joules per mole. The synonym for ionization energy (E_I) is often used. The energy to separate the electron most loosely bound to the atom is the first ionization potential; however, there is some ambiguity in the terminology. Thus, in chemistry, the second ionization potential of lithium is the energy of the process.

In physics, the second ionization potential is the energy required to detach an electron from the next highest energy level of the neutral atom or molecule, e.g.

It can be studied as pi=q/r, where "q" element charge.

Methods for determining ionization energy

The most direct way is by applying atomic spectroscopy. Based on the spectrum of light radiation, which basically gives off colors in the range of visible light, the energy levels required to detach each electron from its orbit can be determined.

Periodic trends in ionization energy

The highlight of the periodic properties of the elements is observed in the increase in ionization energies when we go through the periodic table from left to right, which translates into an associated increase in electronegativity, contraction of atomic size and increase in the number of electrons in the valence shell. The cause of this is that the effective nuclear charge increases over a period, generating increasingly higher ionization energies. There are discontinuities in this gradual variation in both horizontal and vertical trends, which can be reasoned based on the specifics of the electronic configurations.
We are going to highlight some aspects related to the first ionization energy that are inferred by the block and position of the element in the periodic table:

• The alkaline elements, group 1, are those who have less ionization energy relative to the remaining of their periods. This is because of its most external electronic configurations ns¹which facilitates the removal of that electron not attracted by the core, as the electronic layers below n exert their screen effect between the kernel and the electron considered.

• In the alkalinetheran elements, group 2, converge two aspects, effective nuclear load greater and external configuration ns²of great quantum strength, so they have greater ionization energies than their predecessors.

• Evidently, the elements of group 18 of the periodic table, the noble gases, are those that exhibit the greatest energies for their electronic configurations of high quantum symmetry.

• The elements of group 17, halogens, continue in behavior to those of group 18, because they have a high tendency to capture electrons because of their high effective nuclear burden, rather than yielding them, thus achieving the stability of noble gases.

Ionization energy of chemical elements

In general, ionization energies decrease along the columns of the periodic table and increase from left to right over a period of the table. The ionization energy shows a strong anti-correlation with the atomic radius. The following table shows the values of the first ionization energy of the elements expressed in eV:

The more we move to the right and up the periodic table, the higher the ionization energy.