Characteristics of Chalcogens, the chalcogens are the name for the Periodic Table group 16 (V1).
The group consists of the elements: oxygen, sulfur, selenium, tellurium, and polonium.
The name of the group was proposing by Wilhelm Blitz and colleague Werner Fischer.
Both worked at the Institute of Inorganic Chemistry at the University of Hannover, Germany, in 1932.
The term “chalcogens” was derived from the Greek word chaos, meaning “ore formers,” since they all are found in copper ores.
Their compounds are referred to as “chalcogenides.”
These names became popular since they are analogous to group 17(V11), halogens, meaning salt formers, and its compounds, halides as an element, oxygen is a gas.
In contrast, the other group members are solids.
Both oxygen and sulfur we can find in pure form.
All of the elements occur as ions in metal ores.
Characteristics of Chalcogens, the elements of this family have isotopes that vary instability.
Polonium is considered a radioactive element and to be handled with care.
The members of this group show increasing metal character as the atomic number increases.
Both oxygen and sulfur are nonmetals, while selenium and tellurium are metalloids (both are semiconductors), and polonium is a metal.
Bonding characteristics of these elements parallel their metal character.
The smaller group members show a greater tendency to form covalent bonds than the larger members do.
Their electronegativities decrease with increasing atomic number.
This trend explains the lessening of ionic character of the compounds of S – Po that is analogous to those of oxygen.
It is for this reason. Only oxygen can exhibit hydrogen bonding.
This drastically changes the character of these compounds.
If the H2M compounds’ boiling points are comparing, we find that the group shows this hydrogen bonding change.
Since the smallest compound in weight has a boiling point of almost 100° higher than any of the other group members.
All of the elements we can find naturally as ions, most often as 2− ions (except for Po).
Oxidation states of +2, +4, and +6 also be found for S – Po members when combined with O, F, or Cl.
What about the difference in the Oxidation States!
Characteristics of Chalcogens, the electronic structure of the elements can explain the difference in oxidation states.
Oxygen can use only s and p orbitals for bonding.
The larger group members used orbitals in the hybridization and thus can participate in using an expanded octet.
This is visual in compounds and complexions such as SOF4, SF4, SeO42, TeF82.
The elements and their compounds vary in their toxicity.
Interestingly, oxygen and sulfur are essential to all life, while the compounds of selenium, tellurium, and polonium can be toxic.
Selenium is an essential trace element, even though it causes severe disorders at larger concentrations (above 5 ppm).
Tellurium compounds, while being toxic, have never reporting to cause a human fatality.
Since polonium and its compounds are radioactive, they are considering extremely toxic in any concentration.