Rubidium (Rb) has an atomic number of 37, which means it has 37 electrons. To write the electronic configuration of rubidium using the Aufbau principle, we fill the electron orbitals in order of increasing energy levels. Here’s the step-by-step filling according to the Aufbau principle, including subshells:
- 1s² - 2 electrons
- 2s² - 2 electrons
- 2p⁶ - 6 electrons
- 3s² - 2 electrons
- 3p⁶ - 6 electrons
- 4s² - 2 electrons
- 3d¹⁰ - 10 electrons
- 4p⁶ - 6 electrons
- 5s¹ - 1 electron
Putting this all together, the electronic configuration for rubidium is:
1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s¹
This can be simplified using noble gas notation as:
[Kr] 5s¹
where [Kr] represents the electron configuration of Krypton, which accounts for the inner 36 electrons.