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### quantum numbers

Posted: Fri Oct 20, 2017 8:04 pm
During lecture today, it was mentioned that the rows of the periodic table correspond to quantum numbers. What exactly does this mean?

Thanks!

### Re: quantum numbers  [ENDORSED]

Posted: Fri Oct 20, 2017 9:11 pm
What this means is that the rows correspond to n. For example, Sodium is in the third row and it is in the 3rd sub-shell thus its electron configuration is [Ne] 3s^1. (The [Ne] is there since Neon is the last noble gas in the previous row) If it is in the second row, the 2nd sub-shell (2s^how ever many electrons) and so forth.

It gets more complicated in the fourth row with the d sub-shell. For example, the fourth row in the periodic table would have the d sub-level a number behind the row it is in. Let's take Arsenic as an example whose electron configuration is [Ar] 4s^2 3d10 4p3. The d sub-shell is 3 while s and p are 4.

Hope this helps!

### Re: quantum numbers

Posted: Sun Oct 22, 2017 2:05 pm
What happens to the quantum number as you move across the row?

### Re: quantum numbers

Posted: Sun Oct 22, 2017 2:15 pm
Elements of the same period share the same principal quantum number. Atoms do not change principal quantum numbers as you move from left to right across the periodic table.

### Re: quantum numbers

Posted: Sun Oct 22, 2017 4:11 pm
Chloe Blume 1F wrote:What happens to the quantum number as you move across the row?

quantum number l changes as you move across certain groups of atoms in a row. The first two columns in a row will be in the s-orbital, so their l = 0. As we move toward the d-orbital (here you will find the metals), l = 2. The p-orbitals will have an l value of 1, and the f-orbitals will have an l value of 3.

### Re: quantum numbers

Posted: Sun Oct 22, 2017 10:36 pm
what helped me understand was looking at this periodic table with all the electron configurations and testing myself
https://sciencenotes.org/color-periodic ... ions-2015/
the text is pretty small but you can zoom in