Titanium has an atomic number of 22. The following orbital notation for titanium is incorrect. Explain the error in terms of the rules for electron arrangements.

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Question

Titanium has an atomic number of 22. The following orbital notation for titanium is incorrect. Explain the error in terms of the rules for electron arrangements.

Pic Related - http://i.imgur.com/oLUzM.png

matt101 · Answer

The 4s energy sub-level must be filled first since it has a lower energy than the 3d energy sub-level. This means the 3d sublevel only has 2 electrons, not 4, and the electron configuration is [Ar]4s^2 3d^2.