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Keep working through this module. Bonus: hardly any calculations for the next 3 chapters. A really nice break from thermo and quantum mechanics!

Watch the Chapter 9 Lecture videos with the printable lecture notes for chapter 9

NEW: If you have questions or comments on the chapter 9 videos and content, you can join in the optional discussion (not graded or required)

When adding electrons to orbitals, would electrons start filling into a 1s orbital or a 2p orbital? Why? ? electrons fill the 1s first, it's lower in energy
How many electrons can fit into a 3s orbital? How many electrons can fit into the 3p orbital system? ? each orbital can hold up to 2 electrons, so 2 in a 3s orbital and 6 total in the 3p system (there are 3 p orbitals in each energy level)
What is the full electron configuration of Ga? What about Ga³⁺? ?
What are the core electrons in Ga? Which are the valence electrons? ?
Is the energy gap between n=1 to n=2 the same as the gap between n=3 to n=4? ? no, the gaps get smaller as n values get bigger. The 1 to 2 gap is the biggest in E.

Helpful extra video (optional) about electron configurations, if you need more examples.

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