To work backwards and find the element with a given configuration, we first need to find the atomic number of the noble gas mentioned in the notation.
Xe is a noble gas with atomic number 54. This means that the notation of [Xe] represents a count of54 electrons.
The superscript on a subshell represents the number of electrons present in that subshell. So, 6s2 implies that our element has two electrons in the 6s subshell.
Therefore, the total number of electrons in the element =54+2=56
Number of electrons in an atom = Number of protons = Atomic number of the element
Therefore, the atomic number of the element with 56 electrons is 56, and the element with an atomic number of 56 in the periodic table is barium.
Hence, barium (Ba) has the noble gas notation of [Xe]6s2.