Final answer:
The noble gas configuration [Xe] 6s² is actually for barium, not strontium. Strontium's noble gas configuration is [Kr] 5s². the correct option is (c) strontium,
Step-by-step explanation:
The noble gas configuration [Xe] 6s² refers to the electron configuration for an element that has the same inner-shell electron configuration as the noble gas xenon (Xe), followed by two electrons in the 6s sublevel.
The elements that may have this configuration are in the alkaline earth metal group, just after xenon in the periodic table. Looking at the choices provided and considering where the alkaline earth metals are located, the correct option is (c) strontium, which has the atomic number 38 and its ground state electron configuration ends with 5s². When written with the noble gas shorthand, strontium's configuration would be [Kr] 5s², not [Xe] 6s². The element that actually has the noble gas configuration [Xe] 6s² is (c) barium, not strontium.