Effective nuclear charge

[akimhaneul]

---

Members don't see this ad.

There is a destroyer question that talks about the effective nuclear charge of cobalt-59. The explanation says that in the electron configuration (1s2 2s2 2p6 3s2 3p6 4s2 3d7), only 4s2 is the valence electron. Therefore, z effective is z- non valence electrons which is 27-25 = 2

I thought for transition metals d orbitals also count as valence electrons? Why only count 4s in this problem?

It's #344 in the gen Chem section.

Thanks!


Sent from my iPhone using SDN mobile

 

[DAT Destroyer]

There is a destroyer question that talks about the effective nuclear charge of cobalt-59. The explanation says that in the electron configuration (1s2 2s2 2p6 3s2 3p6 4s2 3d7), only 4s2 is the valence electron. Therefore, z effective is z- non valence electrons which is 27-25 = 2

I thought for transition metals d orbitals also count as valence electrons? Why only count 4s in this problem?

It's #344 in the gen Chem section.

Thanks!


Sent from my iPhone using SDN mobile

Organic Chemists and General Chemists often come to blows on this question......with neither side happy. In organic chemistry, we do indeed add the d orbital electrons. This is the cornerstone of Organo-Metallic chemistry....... In General Chemistry we do it differently. The organic chemist assumes since the energy is very close, we add them together, and this works for most purposes, In General Chemistry, we note that their is indeed a slight energy difference. For instance,,,,,if asked to draw out the electron configuration of Fe +2...we simply REMOVE the two valence electrons from the the 4s orbital....and we are left with a d6 specie. If you did this the organic chemist way...LOL.....Good Luck. For exams like the DAT, GRE, ACS exam and the like.....do it like the General Chemist .......and do NOT add the d electrons with the s electrons ! I hope this helps.

Dr. Romano