This metal belongs to the p block. It is soft, gray, malleable and pewter-like, but on contact with air it discolours.
Thallium is quite toxic, it has been used as an insecticide and rodenticide, but this application has been discontinued or reduced in various countries due to its possible carcinogenic effects. It is also used in infrared detectors.
As explained above, the metal is very malleable and soft, so it can be cut with a knife. When exposed to air, it changes from a metallic luster to a rapid tarnish with a bluish and gray tint similar to lead.
The name thallium comes from the Greek “thallos” which means green branch or shoot. It was discovered by flame spectroscopy carried out in 1861. The name derives from the glow of green tint that exists in the lines of the emission spectrum of said element.
Electron configuration of thallium
The electron configuration of the element thallium in its full version is 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2 5p6 4f14 5d10 6s2 6p1, while the simplified or abbreviated electron configuration of thallium is [Xe]4f14 5d10 6s2 6p1.
To know the atomic mass of an element, you must first know the complete mass of the protons of the neutrons that are in a single atom that is part of the element. The atomic mass of thallium is 204.3833 u.
Thallium is located in period 6 and group 13 of the periodic table of chemical elements. The covalent radius of this element is 37 pm, the average radius is equal to 190 pm, the Van Der Waals radius is written as 126 pm, while the Bohr radius or atomic radius of thallium is 156 pm.
Properties of thallium
Thallium composes the group of metallic elements called p-block metals, they are located next to the semi-metals or metalloids of the periodic table of chemical elements. This class of elements are normally soft, have low melting points. The natural state of thallium is solid. It is represented by the chemical symbol Tl and its atomic number is 81.
The boiling point of this element is 1473.85 degrees Celsius or degrees Celsius, similar to 1746 degrees Kelvin. Thallium has a melting point of 304.85 degrees Celsius, or degrees Celsius, equal to 577 degrees Kelvin.
Thallium Configuration Toxicity
Thallium and its compounds are toxic to human life. When the element comes into contact with the skin, it is dangerous. To avoid its inhalation, there must be adequate ventilation during pouring.
Various compounds of this element have high water solubility and are easily absorbed by the skin. Exposure to this element should not be greater than 0.1 mg per m2 on the skin for an average of 8 hours per day, or 40 hours for a week. Thallium is suspected to cause cancer in humans.
One of the reasons why this element is so toxic is that in its aqueous solution as a monovalent thallium ion, several similarities are observed with the cations that the alkali metals possess, mainly potassium. For this reason, thallium can enter the body using the potassium uptake pathway.
On the other hand, other characteristics of the chemistry of this element differ significantly from those of the alkali metals, such as a strong affinity for sulfide bonds. The aforementioned substitution disrupts multiple cellular processes.
The element can attack proteins composed of bridges or disulfide bonds, such as those containing ferredoxin or cysteine. Due to its enormous toxicity, thallium was used in various countries as a rodenticide and to control ants. However, its use is currently restricted in many of these countries as it is considered a probable carcinogen.
One of the most observable effects of thallium poisoning is alopecia and peripheral nerve damage. Before knowing the toxicity of this element, it was initially used as an epilator. The element was a poisonous agent used effectively to cause poisoning deaths before its toxic potential was known and Prussian blue was discovered as an antidote.
