What is important about group 6A from periodic table

The Group 6A is the one where there are observed
variations of properties of the elements.

For example,
Polonium is a metal, tellurium is a metalloid and selenium, sulfur and oxygen are
nonmetals.

Though, there are like properties, such as: all
the elements form oxygen-compounds and sodium-compounds.

In
the Group 6A the 2nd and 3rd period elements have different structures: oxygen has an
allotrope (O3) and sulfur has many allotropes.

Sulfur,
tellurium and selenium are also called chalcogens because they are found in copper ores
(khalkos is the Greek name of copper).

Sulfur is also known
as the "burning stone" and the sulfur compounds are smelling and poisonous. The well
known H2SO4 is an important compound of sulfur.

Sulfur and
selenium are important elements in human diet.