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Name: Joash
Status: student
Grade: other
Country: Malaysia
Date: Spring 2010

Why is platinum's electron configuration [Xe] 4f14 5d9 6s1 instead of [Xe] 4f14 5d8 6s2? I filled the electron configuration according to the order of filling orbitals and 6s subshell is filled before 5d subshell. so why does the 1 electron from the 6s subshell goes to the 5d subshell? is there any general way to spot when to shift the electrons in the s subshells to other subshells?

especially for high atomic number atoms, where "cross over" of orbitals is fairly common. The explanation is fairly involved and to some degree "ad hoc". If you look in a most Inorganic Chemistry texts you will find the explanation at several degrees of difficulty. One, but certainly not the only one, is "Inorganic Chemistry" by James E. Huheey.

Vince Calder

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