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Thallium is a chemical element; it has symbol Tl and atomic number 81. It is a silvery-white post-transition metal that is not found free in nature. When isolated, thallium resembles tin , but discolors when exposed to air.
Thallium is a chemical element with the symbol Tl and atomic number 81. This soft gray other metal resembles tin but discolors when exposed to air. The two chemists William Crookes and Claude-Auguste Lamy discovered thallium independently in 1861 by the newly developed method of flame spectroscopy .
Thallium (81 Tl) has 41 isotopes with atomic masses that range from 176 to 216. 203 Tl and 205 Tl are the only stable isotopes and 204 Tl is the most stable radioisotope with a half-life of 3.78 years. 207 Tl, with a half-life of 4.77 minutes, has the longest half-life of naturally occurring Tl radioisotopes.
This results in a variety of oxidation states. In the lighter elements, the +3 state is the most stable, but the +1 state becomes more prevalent with increasing atomic number, and is the most stable for thallium. [19] Boron is capable of forming compounds with lower oxidization states, of +1 or +2, and aluminium can do the same. [20]
This is a list of chemical elements and their atomic properties, ordered by atomic number ... a purely formal definition as number of electrons ... Thallium: Tl: 204. ...
A chemical element, often simply called an element, is a type of atom which has a specific number of protons in its atomic nucleus (i.e., a specific atomic number, or Z). [ 1 ] The definitive visualisation of all 118 elements is the periodic table of the elements , whose history along the principles of the periodic law was one of the founding ...
The probable effect has been likened to just under 140 atomic bombs going off at once. Number 9. ... lead, and thallium. Number 1. Eating sushi. If the chef offers you a plate of delicious fugu ...
Each distinct atomic number therefore corresponds to a class of atom: these classes are called the chemical elements. [5] The chemical elements are what the periodic table classifies and organizes. Hydrogen is the element with atomic number 1; helium, atomic number 2; lithium, atomic number 3; and so on.