So here if we reimagine the periodic table, we'll see it in this depiction. Now realize here we have blue, we have yellow, we have purple, and we have red sectors. Now, each of these is called a block. The s block is what's in blue, this is the p block, the d block, and the f block. Remember the s sublevel has 1 orbital and that one orbital can hold a maximum of 2 electrons, which is why the s block is these 2 columns, to represent the 2 maximum electrons that the s sublevel can hold. The p sublevel has 3 orbitals, right, and each one again can hold a maximum of 2 electrons. So p theoretically can hold a maximum of 6 electrons. That's why the p block has 1, 2, 3, 4, 5, and 6 slots for it. D can have up to 10 electrons because it has 5 orbitals, and if you count you'll see in here there are 10 spots. And then for the f sublevels, they can hold up to 14 electrons, and if you were to count these rows in red, you'd see they come out to 14.
Now, realize here that in this periodic table, the first slot here which represents hydrogen starts off our electron configuration as s11. Then as we move to the next one we add another electron, so helium is s12. Then when we get to the 2nd row, since we're in the 2nd row, we now have 2. This is still the s block, so this is s12s21, and it continues onward and onward. Over here, we'd go s12s22p21. So following this pattern, this would be s3s4s5s6s7. And then here, this would be p3p4p5p6p7.
When we go to the d block, realize that it's gonna drop down by 1. So here this is s4, but then when we go to d block, it drops down by 1 number, so now it's d3d4d5d6. Now, notice how this number goes from 57 to 72, that's because 58 to 71 are here. Remember this red line here says that this entire red row exists between 57 and 72. And then we go between 89 and 104 because 90 to 103 is down here. These are your f blocks. They also drop down by one number. So this is f4f5. So basically, if you can reimagine the periodic table in this fashion, you can use it to figure out the electron configuration of any element or ion given to you. So we're gonna put this periodic table to use in order to do future electron configurations.