Why do noble gases show the least reactivity

The chemistry side

In the periodic table of the elements, elements with similar properties are perpendicular to each other and are divided into eight main groups and ten subgroups. The main group elements have the greater similarities to one another within their group compared to the subgroup elements.

Although hydrogen is also in the 1st main group in the periodic table, it does not belong to the alkali metals. It is gaseous under normal conditions and has the lowest atomic mass of all elements.

The alkali metals (1st main group) include lithium, sodium, potassium, rubidium and the radioactive francium. Overall, alkali metals are very strong reducing agents because they have one more electron than the noble gas configuration and therefore have a very low ionization energy. They show violent reactions on contact with water and this reaction becomes stronger and increasingly exothermic the further down they are in the group.

The noble gases (8th main group) include helium, neon, argon, krypton, xenon and radioactive radon. They have an outer shell that is completely occupied by electrons, which means that they have extremely low reactivity and very high ionization energy. They are therefore usually not toxic to humans and have no odor. All elements of the 8th main group are in the monatomic, gaseous state under normal conditions. The energetic state of the noble gases is very favorable due to the completely full or empty shells, which is why other elements in reactions try to achieve the noble gas configuration.

The halogens (7th main group) include fluorine, chlorine, bromine, iodine and the radioactive astatine. They lack an electron in the outermost shell for the noble gas configuration, which means that, like the alkali metals, they have a very high reactivity. However, they act as strong oxidizing agents, with their oxidation strength decreasing from fluorine to iodine, have a rather high ionization energy and are very toxic. Fluorine in particular has a very strong reactivity due to its high electron affinity, which means that storage requires special measures. Under normal conditions, fluorine and chlorine are gaseous, bromine liquid and iodine solid. In nature they occur predominantly as negatively charged anions, often together with alkali metals. A well-known example is sodium chloride, the common salt.

The chalcogens (6th main group) include oxygen, sulfur, selenium, tellurium and the radioactive polonium. They are moderately reactive and, together with metals, form the metal chalcogen compounds, such as oxides or sulfides. The density as well as the melting and boiling point increase from oxygen to tellurium. To obtain oxygen, the Linde process can be used, among other things, in which air is first compressed, then the resulting heat is dissipated and the air is then expanded again. The expansion of the gases cools the air and the process is repeated until the air is liquid. Then the individual gases can be obtained by distillation.

The nitrogen group (5th main group) includes nitrogen, phosphorus, arsenic, antimony and bismuth. With the exception of nitrogen, all elements in this group are solids and, with the exception of nitrogen and phosphorous, have metallic properties. In addition, nitrogen and phosphorus are two very important elements in biochemistry. Nitrogen is an important component in the purine and pyrimidine bases of DNA and in amino acids, and phosphorus, together with ribose, forms the backbone of the DNA or RNA strands.

The carbon group (4th main group) includes carbon, silicon, germanium, tin, lead and the radioactive flerovium. The elements of this group show a very different behavior with regard to their properties, among other things because the group contains one non-metal (carbon), two semi-metals (silicon, germanium) and three metals (tin, lead, flerovium) . However, carbon is worth mentioning because it is the central atom of organic chemistry and the basis of life on earth. Its outer shell, only half filled with four electrons, enables complex connections with many other elements.

The boron group (3rd main group) includes boron, aluminum, gallium, indium and thallium. With the exception of boron, all elements of this group are metals and aluminum is the most common metal in the earth's crust. Today it is widely and widely used as a material in a wide variety of industries.

The alkaline earth metals (2nd main group) include beryllium, magnesium, calcium, strontium, barium and radioactive radium. Like alkali metals, alkaline earth metals also react violently with water and form relatively strong bases.

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