The inert gases, Also known as rare or noble gases, they are those that do not have an appreciable reactivity. The word 'inert' means that the atoms of these gases are not capable of forming a considerable number of compounds and some of them, like helium, do not react at all.
Thus, in a space occupied by inert gas atoms, these will react with very specific atoms, regardless of the pressure or temperature conditions to which they are subjected. In the periodic table they make up the group VIIIA or 18, called the group of noble gases.
The upper image corresponds to a bulb filled with xenon excited by an electric current. Each of the noble gases is able to shine with its own colors through the incidence of electricity.
Inert gases can be found in the atmosphere, although in different proportions. Argon, for example, has a concentration of 0.93% of the air, while neon of 0.0015%. Other inert gases emanate from the sun and reach the earth, or are generated in its rocky foundations, being found as radioactive products..
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Inert gases vary according to their atomic beds. However, they all present a series of characteristics defined by the electronic structures of their atoms..
Traversing any period of the periodic table from left to right, the electrons occupy the orbitals available for an electronic shell n. Once the s orbitals have been filled, followed by the d (from the fourth period) and then the p orbitals.
The block p is characterized by having an electronic configuration nsnp, giving rise to a maximum number of eight electrons, called the valence octet, nstwonp6. The elements that present this completely filled layer are located at the extreme right of the periodic table: the elements of group 18, that of the noble gases.
Therefore, all inert gases have complete valence shells with ns configurationtwonp6. Thus, varying the number of n each of the inert gases is obtained.
The only exception to this characteristic is helium, whose n= 1 and therefore lacks p orbitals for that energy level. Thus, the electron configuration of helium is 1stwo and it does not have one valence octet, but two electrons.
Noble gas atoms can be visualized as isolated spheres with very little tendency to react. By having their valence shells filled, they do not need to accept electrons to form bonds, and in addition, they have a homogeneous electronic distribution. Therefore, they do not form bonds or between themselves (unlike oxygen, Otwo, O = O).
Being atoms, they cannot interact with each other through dipole-dipole forces. So the only force that can momentarily hold two atoms of inert gases together are the London or scattering forces..
This is due to the fact that, even being spheres with homogeneous electronic distribution, their electrons can originate very short instantaneous dipoles; enough to polarize a neighboring inert gas atom. Thus, two B atoms attract each other and for a very short time form a BB pair (not a B-B bond).
As a result of the weak London forces that hold their atoms together, they can barely interact to show up as colorless gases. To condense into a liquid phase, they require very low temperatures, thus forcing their atoms to “slow down” and the BBB interactions last longer ···.
This can also be achieved by increasing the pressure. By doing this, it forces its atoms to collide with each other at higher speeds, forcing them to condense into liquids with very interesting properties..
If the pressure is very high (tens of times higher than atmospheric), and the temperature is very low, the noble gases can even pass into the solid phase. Thus, inert gases can exist in the three main phases of matter (solid-liquid-gas). However, the conditions necessary for this demand laborious technology and methods..
Noble gases have very high ionization energies; the highest of all the elements in the periodic table. Why? For the reason of its first feature: a full valence layer.
By having the valence octet nstwonp6, removing an electron from a p orbital, and becoming a B ion+ electron configuration nstwonp5, requires a lot of energy. So much so that the first ionization energy I1 for these gases it has values that exceed 1000 kJ / mol.
Not all inert gases belong to group 18 of the periodic table. Some of them simply form strong and stable enough bonds that they cannot be easily broken. Two molecules frame this type of inert gas: nitrogen, Ntwo, and that of carbon dioxide, COtwo.
Nitrogen is characterized by having a very strong triple bond, N≡N, which cannot be broken without extreme energy conditions; for example, those triggered by an electrical lightning bolt. While the COtwo It has two double bonds, O = C = O, and is the product of all combustion reactions with excess oxygen.
Designated with the letters He, it is the most abundant element in the universe after hydrogen. It forms about a fifth of the mass of stars and the sun.
On Earth, it can be found in natural gas reservoirs, located in the United States and eastern Europe..
The rest of the noble gases of group 18 are Ne, Ar, Kr, Xe and Rn.
Of all of them, argon is the most abundant in the earth's crust (0.93% of the air we breathe is argon), while radon is by far the rarest, a product of the radioactive decay of uranium and thorium. Therefore, it is found in various terrains with these radioactive elements, even if they are found deep underground..
Because these elements are inert, they are very useful to displace oxygen and water from the environment; in order to guarantee that they do not intervene in certain reactions where they alter the final products. Argon finds a lot of use for this purpose.
They are also used as light sources (neon lights, vehicle lanterns, lamps, laser beams, etc.).
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