Question 22.2: Writing Electron Configurations for Transition Metals Write...
Writing Electron Configurations for Transition Metals
Write the ground state electron configuration for Co^{3+}.
Identify the noble gas that precedes the element and write it in square brackets.
[Ar]
Count down the periods to determine the outer principal quantum level this is the quantum level for the s orbital.
Subtract one to obtain the quantum level for the d orbital. If the element is in the third or fourth transition series, include (n – 2)f ^{14}electrons in the configuration.
Co is in the fourth period, so the orbitals used are
[Ar] 4s3d
Count across the row to see how many electrons are in the neutral atom and fill the orbitals accordingly.
Co has nine more electrons than Ar.
[Ar] 4s^23d ^7
For an ion, remove the required number of electrons, first from the s and then from the d orbitals.
Co^{3+} has lost three electrons relative to the Co atom.
[Ar] 4s^03d^6 or [Ar] 3d^6