Writing Electron Configurations Help

[Anish Patel 4B]

In class, Dr. Lavelle said to write configurations in order of increasing energy. However, in the book it gives examples/answers in a different way where the configuration is written in the order of increasing coefficients for each sublevel (Ex for bismuth: [Xe] 4f^14, 5d^10, 6s^2, 6p^3). Does the book do it correctly/did I hear the professor incorrectly or is there a reason for why they are different?

[emma brinton_3B]

i am unsure :/ i was attempting problems too and was a little confused but i know for electron configurations it should be written in the order seen in this picture
https://www.google.com/search?q=electro ... TSSWgFph3M:
also here is a helpful youtube video:
https://www.youtube.com/watch?v=NIwcDnFjj98

[Emma Popescu 1L]

This confused me as well and I am not sure about the textbook. However, in a test the electron configuration should definitely be written from lowest to highest energy level.

[Ashley Tran 2I]

The textbook answer is in increasing n (principal quantum number) for bismuth [Xe] 4f14 5d10 6s2 6p3. Which is the convention in my experience.

Dr. Lavelle might have been explaining how to write electron configurations in increasing energy to understand which orbitals get filled first with electrons. For example, 4s orbitals have a lower energy than the 3d so the 4s orbitals are filled first even though the number 4 is greater than 3 and people might think 3d gets filled first for this numerical reason.