Electron Configuration for Transition Metals

[Rachel Kho Disc 2G]

I’m a little lost in my understanding of electron configuration and orbital diagrams for transition metals and charged particles, especially in terms of Focus 2A. (ex. 2A.3a, 2A.5, 2A.19b, 2A.19d, 2A.21d). Could someone help explain how to figure out these types of problems?

[ColmConnolly3D]

The key things for me are when you count up, you start with the s orbitals and when you count down, like with ions, those are the first to go. You also need to remember the exceptions to this general rule with chromium (3d5 4s1) and copper (3d10 4s1) both moving an s orbital electron to the d orbital to have a fully filled 3d subshell. With these basic rules, just count up along the periodic table, and more often than not you will come out on top.

Hope this helps!

[SavannahScriven_1F]

Adding on to a specific part of the previous response, it helps me to realize that the 4s orbitals fill up first, but once there is an electron in a 3d state, it has lower energy than those in 4s. That's why 3d is written before 4s, even though the periodic table shows that 4s is before 3d. That's also why you write that transition metals lose 4s electrons to from ions before 3d electrons.

[Kayko Lee 1C]

For the electron configurations I just keep an eye out if the transition metal in the configuration has 4 or 9 electrons because then you def want to fill it to 5 or 10 electrons by taking away an electron from the s orbital and adding it to the d orbital. As for orbital diagrams it helps when I visualize it so for the d block I draw 5 boxes and fill up the boxes according to hunds and aufbaus principle, and for the p orbital I draw 3 boxes and do the same process and I can see which electrons are unpaired/unpaired