destroyer gc unpaired e-'s #100

[Kneecoal]

---

Members do not see this ad.

Asking which has the most unpaired electrons - out of answer choices Na, I, Fe, Cu, and Cr...

I can see how Na, I, and Fe aren't (1, 1, and 4)

And I can see how Cu fills up to 3d10 4s1 instead of 4s2 3d9... (4)

But I don't understand why Cr fills up like 4s1 3d5 for 6 unparied e-'s

Can someone explain this to me?

 

[DoctaWalnuts]

A d orbital wants to be half full or completely full. This will effect Cr and Cu.

So to make Cu a half full d orbital (5/10) you need to take one electron out of the 4s orbital.

 

[PooyaH]

the filling of last d orbital would lower the energy of Cr and therefore it becomes more stable!

 

[Kneecoal]

A d orbital wants to be half full or completely full. This will effect Cr and Cu.

So to make Cu a half full d orbital (5/10) you need to take one electron out of the 4s orbital.

oh - i didn't know it could want to be half full instead of completely full too. thanks!

 

[DoctaWalnuts]

oh - i didn't know it could want to be half full instead of completely full too. thanks!

yes half too. I don't remember why though. I know there is a good reason for it though.

 

[Sublimation]

Asking which has the most unpaired electrons - out of answer choices Na, I, Fe, Cu, and Cr...

I can see how Na, I, and Fe aren't (1, 1, and 4)

And I can see how Cu fills up to 3d10 4s1 instead of 4s2 3d9... (4)

But I don't understand why Cr fills up like 4s1 3d5 for 6 unparied e-'s

Can someone explain this to me?

Only for the first row of the transitional metals will you see this behavior. (old)

Only for the first row of the transitional elements will you see 4s and 3d be equal in energy. Knowing this exception to the aufbea<-( I kno i spelled that wrong) is will come in handy. Knowing all the exceptions will be beyond the scope of the DAT.