Question

Why is the electronic configuration of potassium 2,8,8,1 and not 2,8,9

Answer 1

In writing the electron configuration for Potassium the first two electrons will go in the 1s orbital. Since 1s can only hold two electrons the next 2 electrons for Potassium go in the 2s orbital. The next six electrons will go in the 2p orbital. The p orbital can hold up to six electrons. We'll put six in the 2p orbital and then put the next two electrons in the 3s. Since the 3s if now full we'll move to the 3p where we'll place the next six electrons. We now shift to the 4s orbital where we place the remaining electron. Therefore the Potassium electron configuration will be 1s²2s²2p⁶3s²3p⁶4s¹