Electron Configuration.

[Jaba]

can anyone tell me if this is too specific:

for electron configuration, there are several odd configurations that don't follow the electron adding rules completely:

i.e
Cr (24) , Cu (29), Nb (41), Mo (42), Ag (47) etc these have incomplete s orbital b/c they fill the d orbital first... Should we be familiar with these elements and their discrepancy, and if so, has anyone come up with a good way to memorize these.

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[dentalplan]

yes. they are transition metals so they are weird. if u look at the perio table, you will see they fill their 3d orbitals first, before their 4s.

 

[bigstix808]

none of that is weird...it is just part of gen chem...4s fills up first before 3d (use n+l rule). you need to know it and be able to recognize it. if you know the basic rules then you're fine. good luck!

 

[Jaba]

yes. they are transition metals so they are weird. if u look at the perio table, you will see they fill their 3d orbitals first, before their 4s.

yaaa, but most of them actually dont... like most of the other ones (sc, Ti, V, Mn, Fe, Co, Ni) etc et cetc all have their s filled before they add to the d. Its only these few odd cases here and there where it is the 3d that almost pulls it away from s.

I have many written down, but i wonder how important it is to know these by heart.

 

[dentalplan]

yaaa, but most of them actually dont... like most of the other ones (sc, Ti, V, Mn, Fe, Co, Ni) etc et cetc all have their s filled before they add to the d. Its only these few odd cases here and there where it is the 3d that almost pulls it away from s.

I have many written down, but i wonder how important it is to know these by heart.

o lol i think i see what ur sayin now. ya those exceptions that you mentioned are even weirder. but not really, because what theyre tryin to do is establish the most stable form they can. true -- they break conventional filling rules, when it comes to transition metals. but who cares, lol. everyone breaks rules, even molecules my good sir. i doubt you need to know them. theyre not even mentioned in my college chem text lol.

 

[ucla2134]

yaaa, but most of them actually dont... like most of the other ones (sc, Ti, V, Mn, Fe, Co, Ni) etc et cetc all have their s filled before they add to the d. Its only these few odd cases here and there where it is the 3d that almost pulls it away from s.

I have many written down, but i wonder how important it is to know these by heart.

Cu, Ag, Au: The completely filled d sublevel of these elements confers stability to the atom at the expense of unfilling the previous s sublevel.
Cr, Mo: Half filled d sublevel confers stability.

--> These are elements that are exception to aufbau ordering so i think knowing them wont harm you

 

[dentalplan]

Cu, Ag, Au: The completely filled d sublevel of these elements confers stability to the atom at the expense of unfilling the previous s sublevel.
Cr, Mo: Half filled d sublevel confers stability.

--> These are elements that are exception to aufbau ordering so i think knowing them wont harm you

ya i know- just read my last post

 

[userah]

i actually wouldn't be too surprised if it came up. it def is discussed in the textbook and i've seen it come up in a few practice exams..