O tellurium, which is the element of atomic number 52 and one a metal of the oxygen group, it has six electrons in its valence shell.. Rare, it occupies the 70th position of abundance in the Earth's crust, with a concentration of approximately 0.001 ppm (part per million). It exists in its native form, but is most commonly found in minerals such as calaverite, krennerite, tellurite and melonite.
See too: Aluminum - metal from the boron family widely used in our daily lives
Tellurium properties
- Symbol: You
- Pastaatomic: 127.6 u.
- Numberatomic: 52.
- electronegativity: 2,1.
- Settingselectronics: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p4.
- Serieschemistry: semimetal, chalcogen, toxic heavy metal, 5th period element.
- PointinFusion: 449.5 °C.
- Pointinboiling: 989.9°C.
Tellurium characteristics
They exist eight natural tellurium isotopes, with atomic masses ranging from 120 to 130, the latter being the most common. Although some are radioactive, this radioactivity is low. Tellurium-128 is the radioisotope with the longest known half-life. This element forms compounds such as tellurium dioxide, tellurium hexafluoride, tellurium dichloride, tellurium dibromide, zinc telluride and hydrogen telluride, in addition to organic compounds.
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Being a semimetal, tellurium have two allotropes: the crystalline and the amorphous. Furthermore, this element is also a semiconductor, and its conductivity varies according to the atomic organization of the sample. He chemically reacts with most existing elements, and tellurides are the most stable compounds. Because it's not as electronegative as the oxygen it's the sulfur, there is the existence of tellurium compounds with positive oxidation states. It has a white color and a metallic shine.
tellurium history
With a silver metallic appearance, the tellurium was discovered around 1782, by the Austro-Hungarian mineralogist Franz Joseph Müller von Reichenstein, who worked in a mine in Transylvania. The ore, which had a characteristic metallic luster, caught his attention, and he suspected it was a antimony native or bismuth (chemical elements). After preliminary investigation, he concluded that it was a gold telluride or the so-called calaverites, which are rare minerals found in nature.
For some years, the scholar researched the ore and he proved that in him there was the presence of a new element. He published his studies and findings in a little-known journal, which went unnoticed. In 1796, he sent a sample to the German pharmacist Martin Klaproth in Berlin, who confirmed his findings to him and produced a pure sample, which was named tellurium.
See too: Nitrogen - the most abundant element in the Earth's atmosphere
Obtaining tellurium
Found mainly as telluride (compound formed by the combination of tellurium and a more electropositive element or aggregate) in ores of gold, silver, copper and nickel, tellurium is obtained during industrial copper beneficiation procedures, that is, as a by-product of copper refining. It has eight natural and nine radioactive isotopes, with a relatively low melting point (449.5 °C). easily suffer oxidation, when in the presence of oxygen.
Tellurium applications
The industry that consumes the most tellurium is metallurgy, as this element is important in alloys for cast iron, stainless steels, copper and lead alloys. It is applied in small amounts to some steels and lead to increase the mechanical strength of these elements. Its chemistry is similar to sulfur, although it has many properties of the metal.
It breaks quite easily and does not have the ability to conduct electrical current very well. For this reason, it is used in the doping of silver, gold, copper or tin for semiconductor manufacturing.
It can also be applied to:
- vulcanize rubber;
- tinting glass and ceramics;
- solar cells;
- rewritable CDs and DVDs;
- catalyst in the refining of Petroleum.
Tellurium is applied medicinally for the detection of the causative organism of diphtheria (infection caused by the bacteria Corynebacterium diphtheriae). The exam can be done using a special medium with tellurium oxide.
Tellurium precautions
For your chemical to be similar to sulfur, it can be deduced that tellurium has properties that result in a bad smell. There are within the variants of this element those with low molecular weight and low volatility, thus requiring greater care in its management, due to this very strong and pervasive odor, which requires avoiding contact with the skin and its inhalation.
solved exercises
Question 1 - Review the following statements about the tellurium element and judge them as true (T) or false (F).
I – Because its chemistry is similar to sulfur, one can imagine that tellurium has properties that result in a pleasant and mild odor.
II – Combining with most elements, metals and non-metals, it is absorbed by the human body and eliminated by breathing and/or sweat, in the form of bad smelling organic compounds.
III – Among the variants of this element, there are those with high molecular weight and low volatility.
A) VFF
B) FVF
C) VVV
D) FFV
E) FFF
Resolution
Alternative B. Alternatives I and II are incorrect as tellurium has properties that result in bad smell and, among the variants of this element, there are those with low molecular weight and low volatility.
Question 2 - Which chemical element listed below has chemical properties and characteristics similar to sulfur (S)?
A) Gallium (Ga).
B) Rubidium (Rb).
C) Beryllium (Be).
D) Tellurium (Te).
E) None of the alternatives.
Resolution
Alternative D. The element that has chemical properties and characteristics similar to sulfur, such as a bad smell, is tellurium.
By Laysa Bernardes Marques de Araújo
Chemistry teacher