Whats the electron configuration for an atom that has 13 electrons

2 electrons on the first ring, 8 on the second, and 3 on the third ring

In order to write the Aluminium electron configuration we first need to know the number of electrons for the Al atom (there are 13 electrons). When we write the configuration we'll put all 13 electrons in orbitals around the nucleus of the Aluminium atom.

In writing the electron configuration for Aluminium the first two electrons will go in the 1s orbital. Since 1s can only hold two electrons the next 2 electrons for aluminium go in the 2s orbital. The nex 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 remaining electron. Therefore the Aluminium electron configuration will be 1s22s22p63s23p1.