What is electronic configuration?

I have a lot to type. So please read till the end to get a complete full understanding on what an electronic configuration is. An electronic configuration in simple terms is like a specific “fingerprint” for an element. No 2 elements have the same configuration. It’s extremely easy to find the configuration of an element, it just takes a lot of time and writing/typing (especially for the elements with atomic numbers over 54). But how do you actually find the electronic configuration of an element? Well, like I said it’s extremely easy but it may be time consuming. But there are 4 different sections on the periodic table (I attached a specific periodic table below to help you understand where each section is). There is S, D, P, and F. What you do is you start with Hydrogen(H) and Helium(He) since those are the first 2 elements on the Periodic table and they are in the S group which is all the way to the left of the table. Helium is above the P section on the table but don’t let that confuse you, Helium will always be part of the S group. But let’s start off with finding the configuration of Oxygen(O). The electronic configuration of Oxygen is 1S2, 2S2, 2P4. The first part of the configuration is 1S2 because 1S was the very first row and it had 2 elements in that row. The second part of the configuration is 2S2 because it was the second row of S and it had 2 elements in that row. Remember that we will always read the periodic table from left to right. Then we had 2P4. There isn’t a 1P on the periodic table. The first row of P is called 2P. But the third part of the configuration is 2P4 because it’s considered the second row of P and Oxygen was the 4th element in that row. Since you are just now learning what an electronic configuration is you probably won’t work with the F group much. If I were you I’d save the periodic table I attached and it will help you out a lot in this unit of chemistry. Your best bet is going online to do more research if you still don’t understand. I hope I helped, I explained the best I could.

The problem here is that according to aufbau principle before 3d orbital 4s subshell comes.after filling 3p orbital with electrons you have 4 electrons left, you place two in 4s with opposite spin and the other two in 3d in any of its two orbitals of total five orbitals with the same spin.