## quantum numbers [ENDORSED]

Irma Ramos 2I
Posts: 51
Joined: Fri Sep 29, 2017 7:07 am

### quantum numbers

During lecture today, it was mentioned that the rows of the periodic table correspond to quantum numbers. What exactly does this mean?

Thanks!

Mikaila 3E
Posts: 21
Joined: Fri Sep 29, 2017 7:07 am

### Re: quantum numbers  [ENDORSED]

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!

Chloe Blume 1F
Posts: 15
Joined: Fri Sep 29, 2017 7:04 am

### Re: quantum numbers

What happens to the quantum number as you move across the row?

Shanmitha Arun 1L
Posts: 53
Joined: Fri Sep 29, 2017 7:04 am
Been upvoted: 1 time

### Re: quantum numbers

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.

JonathanLam1G
Posts: 25
Joined: Fri Sep 29, 2017 7:04 am

### Re: quantum numbers

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.

Ilan Shavolian 1K
Posts: 58
Joined: Fri Sep 29, 2017 7:03 am

### Re: quantum numbers

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