writing electron configurations?

Janet Nguy 2C
Posts: 74
Joined: Sat Aug 24, 2019 12:17 am

writing electron configurations?

Hi, I'm confused on how to determine an element's electron configuration... first, how do you know if something is in the s state/p state/etc... and how do you then fill out the electron configuration? Any explanations are helpful, thank you!

kevinchang_4I
Posts: 55
Joined: Tue Nov 13, 2018 12:17 am

Re: writing electron configurations?

I guess you kinda have to memorize the order. It goes 1s2, 2s2, 2p6, 3s2, 3p6, 3d10, 4s2,4p6....

The exponents are keep track of the number of electrons. For example, if my electron configuration was 1s2, 2s2, 2p3, then I know my element has 7 electrons, and must be Nitrogen. This rule applies to the whole periodic table, just sometimes a bit longer and harder.

Jason Wu 1E
Posts: 65
Joined: Thu Jul 25, 2019 12:15 am

Re: writing electron configurations?

To determine an electron's configuration, all you need to do is to find where the element is on the periodic table and follow the sequence to get it (sequence will always be 1s^2 2s^2 2p^6 etc.). You could write the shortcut for it by starting with the most recent noble gas that has a smaller atomic number than the element you are searching for in brackets. After that, start with the energy state with the smallest sequence (usually d and f blocks if your element passes it or is in it), then progress to how many electrons are in the s orbital then finish it with how many there is in the p orbital.

Exceptions:
If your element is Cr, Mo, W or Sg then the d block will be powered 5 (instead of 4) and the s block for the following state is lowered to power 1.
If your element is Cu, Ag, Au, or Rg then your d block will be powered 10 (instead of 9) and the s block for the following state is lowered to power 1.
If your element is Eu or Am, then the f block is powered 7 (instead of 6) and the electron from the d block for the following state is removed.
If your element is Yb or No, then the f block is powered 14 (instead of 13) and the electron from the d block for the following state is removed.

Brittany Tran 3I
Posts: 50
Joined: Sat Jul 20, 2019 12:16 am

Re: writing electron configurations?

you can just follow the order of the elements on the periodic table to find electron configurations. if an element is in the s-block, the s orbital will be filled first. if the element is in the p-block, the s orbital is filled first, then the p orbital is filled.

Kaitlyn Jang 1F
Posts: 45
Joined: Sat Aug 17, 2019 12:16 am

Re: writing electron configurations?

You can look up a periodic table that is color coded orbital, and use that to guide you through the configurations. Typically, the elements in the first 2 groups are s orbitals, 3-12 is d orbital, and 13-18 (excluding Helium witch is s-orbital) are p-orbitals. For example, to find the electron configuration for Nitrogen, you start at the top with Hydrogen, which is 1s1, then He is 1s2 (but just write 1s2), Li is 2s1, Be is 2s2 (but just write 2s2), B is 2p1, C is 2p2, and N is 2p3 (but just write 2p3). The final electron configuration for Nitrogen is 1s2 2s2 2p3.