* Find Cesium's Atomic Number: Cesium has an atomic number of 55, meaning it has 55 protons and 55 electrons.
* Identify the Previous Noble Gas: The noble gas that comes before cesium on the periodic table is Xenon (Xe), which has an atomic number of 54.
* Write the Noble Gas Core: The noble gas core is the electron configuration of the previous noble gas. So, the core for cesium is [Xe].
* Add the Remaining Electrons: Cesium has one more electron than Xenon (55 - 54 = 1). This electron goes into the 6s orbital.
Therefore, the noble gas configuration of cesium is [Xe] 6s¹
