The chalcogen having same number of electrons both in penultimate and antipenultimate shells is

Tellurium (Te) is the chalcogen which contains same number of electrons both in penultimate as well as antepenultimate shell.

Explanation:

·       The elements of group sixteen in the periodic table is called Chalcogen.

·       All chalcogen have six electrons in their valence shell.

Electron distribution in chalcogens:

  Element        No. of electros/shell                

 Oxygen            2,6

Sulfur                2,8,6

Selenium          2,8,8,18,6

Tellurium        2,8,8,18,18,6         

Therefore, Tellurium has 18 electrons in its penultimate as well as antepenultimate shell.