Answer : The noble gas notation is often given to the short or abbreviated form of the electron configuration.
The use of symbol of the previous noble gas as part of the electron configuration of an element is the shortcut way to write the electron configuration.
Xenon has electron configuration as [tex] 1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 3d^{10} 4s^{2} 4p^{6} 4d^{10} 5s^{2} 5p^{6} [/tex].
Cesium has the electron configuration as [tex] 1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 3d^{10} 4s^{2} 4p^{6} 4d^{10} 5s^{2} 5p^{6} 6s^{1} [/tex]
So, Cesium can be abbreviated using the symbol of xenon [Xe] [tex] 6s^{1} [/tex].
