Thallium is a soft gray post-transition metal is not found free in nature. Commercially, thallium is produced as a byproduct from refining of heavy metal sulfide ores. Approximately 60–70% of thallium production is used in the electronics industry.
Protons and Neutrons in Thallium
Thallium is a chemical element with atomic number 81 which means there are 81 protons in its nucleus. Total number of protons in the nucleus is called the atomic number of the atom and is given the symbol Z. The total electrical charge of the nucleus is therefore +Ze, where e (elementary charge) equals to 1,602 x 10-19 coulombs.
The total number of neutrons in the nucleus of an atom is called the neutron number of the atom and is given the symbol N. Neutron number plus atomic number equals atomic mass number: N+Z=A. The difference between the neutron number and the atomic number is known as the neutron excess: D = N – Z = A – 2Z.
For stable elements, there is usually a variety of stable isotopes. Isotopes are nuclides that have the same atomic number and are therefore the same element, but differ in the number of neutrons. Mass numbers of typical isotopes of Thallium are 203, 205.
Main Isotopes of Thallium
Thallium occurs in 2 natural isotopes: 203Tl and 205Tl. 205Tl is the most common isotope, having a natural abundance of approximately 70%.
Thallium-203 is composed of 81 protons, 122 neutrons, and 81 electrons.
Thallium-205 is composed of 81 protons, 124 neutrons, and 81 electrons.
Electrons and Electron Configuration
The number of electrons in an electrically-neutral atom is the same as the number of protons in the nucleus. Therefore, the number of electrons in neutral atom of Thallium is 81. Each electron is influenced by the electric fields produced by the positive nuclear charge and the other (Z – 1) negative electrons in the atom.
Since the number of electrons and their arrangement are responsible for the chemical behavior of atoms, the atomic number identifies the various chemical elements. The configuration of these electrons follows from the principles of quantum mechanics. The number of electrons in each element’s electron shells, particularly the outermost valence shell, is the primary factor in determining its chemical bonding behavior. In the periodic table, the elements are listed in order of increasing atomic number Z.
Electron configuration of Thallium is [Hg] 6p1.
Possible oxidation states are +1,3.
Most Common Application of Thallium
The use of thallium is limited as it is a toxic element. Thallium is rarely used, with the exception of the manufacture of special grades of glass. Most thallium is used by the electronics industry in photoelectric cells. Thallium oxide is used to produce special glass with a high index of refraction, and also low melting glass that becomes fluid at about 125K.
|Number of protons||81|
|Number of neutrons (typical isotopes)||203, 205|
|Number of electrons||81|
|Electron configuration||[Hg] 6p1|
Properties of other elements