Final answer:
An element with a 6d² highest occupied subshell would most likely be found among the transition metals or actinides in the 6th period of the periodic table. The exact identity of such an element cannot be determined without its atomic number, but it would follow after the 5d subshell is filled with 10 electrons.
Step-by-step explanation:
An element with 6d² as its highest occupied subshell is likely to be found among the transition metals or the actinides series of the periodic table. When determining such an element, it's essential to understand the electron configuration, especially the order in which electrons populate the subshells. According to Aufbau principle, lower energy subshells fill before higher energy subshells, and the d-subshell is actually the (n-1)d subshell, where n represents the principal quantum number of the highest occupied principal energy level in ground state atoms.
From the information provided, for example, we know that the 4s subshell is filled before the 3d subshell, and the 3d subshell can accommodate up to 10 electrons. Beginning with the transition metal scandium, with atomic number 21, we see electrons added to the 3d subshell, followed by the 4p subshell for elements that follow. Similarly, for elements with a 6d² highest occupied subshell, they would begin to fill after the 5d subshell has been populated with 10 electrons. Therefore, the element you are asking about likely belongs to the 6th period of the periodic table and has an electron configuration that ends in 6d².
However, the actual element with a 6d² electron configuration as its ground state cannot be determined without additional context or a specific atomic number since this knowledge would be necessary to map the exact position within the periodic table. Typically, the elements which have a partially filled 6d subshell are located in the actinides series or might be among the recently discovered superheavy elements, which have atomic numbers beyond those found in natural conditions.