Electron configuration

My class looked at this briefly so am I right in saying that whichever group is at the end of the structure is what block it is in?

For example for
1s^2 2s^2 2p^6 ….. 3d^6
Would be in group d because it’s at the end?

But an exception would be for example
1s^2 2s^2 2p^6 ….. 3d^6 4s^2
Because 4s fills before 3d, so would it still be group d?

Thanks
Original post by study23!
My class looked at this briefly so am I right in saying that whichever group is at the end of the structure is what block it is in?

For example for
1s^2 2s^2 2p^6 ….. 3d^6
Would be in group d because it’s at the end?

But an exception would be for example
1s^2 2s^2 2p^6 ….. 3d^6 4s^2
Because 4s fills before 3d, so would it still be group d?

Thanks

If you look at a periodic table and count through the 1s^2 2s^2 2p^6… you'll see that the "4s" elements (K and Ca) come before the "3d" elements (Sc–Zn) 4s fills before 3d (and 5s before 4d etc). So in your 1s^2 2s^2 2p^6 ….. 3d^6 4s^2 example you'd count the 2 x 4s elements then count to the 6th 3d element, which is Fe (a d-block element). I don't think it matters which way round the 3d^6 and 4s^2 go; I tend to do s then d

https://pubchem.ncbi.nlm.nih.gov/periodic-table/

I find it easiest to count (not necessarily one by one, just through the blocks until I get to the one of interest )
Original post by bl0bf1sh
If you look at a periodic table and count through the 1s^2 2s^2 2p^6… you'll see that the "4s" elements (K and Ca) come before the "3d" elements (Sc–Zn) 4s fills before 3d (and 5s before 4d etc). So in your 1s^2 2s^2 2p^6 ….. 3d^6 4s^2 example you'd count the 2 x 4s elements then count to the 6th 3d element, which is Fe (a d-block element). I don't think it matters which way round the 3d^6 and 4s^2 go; I tend to do s then d

https://pubchem.ncbi.nlm.nih.gov/periodic-table/

I find it easiest to count (not necessarily one by one, just through the blocks until I get to the one of interest )

Thanks 😊