Confusion on e- Notes

[104922499 1F]

I missed lecture, but I got notes from a friend and I noticed for the e- configuration for Cu it was written as: [Ar] 3d^104s^1
I was confused why there is a bracket around Ar? Is it just a shorter notation or way to write the configuration?

[David Minasyan 1C]

Yes that's exactly what that means. It's called the noble gas configuration if we we're being fancy and it's really a short hand way of writing the noble gas configuration up to the noble gas (in this case argon) instead the whole 1s2, 2s2, 2p6..and so on.

[404995677]

He also said in the lecture that the chemical short hands are encouraged to be used on quizzes and tests