有關d orbital

Question

我知4s係低energy 過3d orbital(if 未fill)

以phosphorus為例
其實點解佢的hybridization要sp3d
即1個3s 3個3p 1個3d
點解唔可以sp3s
即1個3s 3個3p 1個4s

係咪hybridization就一定要same shell of electron
唔洗理佢地之間的energy差異嗎?

PCl5 真係sp3d wor

PCl5 真係sp3d wor

佢3s electron can be excited into 3d orbital
thus 5個相等energy orbitals for 5 bonds

在phosphorus黎講
由於佢係冇3d electron在ground state
so 4s orbital 係照理lower energy than 3d orbital

但為左想form 5個bonding 就expand its low lying d orbital
成sp3d 5個orbital

但我最唔明係點解有得揀佢唔揀當時較少energy gap的4s and 3p
而要選3p and 3d 呢???

Answer 1

The statement「the 4s subshell has a lower energy level than the 3d subshell」is NOT always correct.

From H (1s1) to Ar (1s2 2s2 2p6 3s2 3p6), the 3d subshell has a lower energy level than the 4s subshell. (In these atoms, none of 3d and 4s subshells are filled.)
For K (1s2 2s2 2p6 3s2 3p6 4s1) and atoms of greater atomic number, the 4s subshell has a lower energy level than the 3d subshell.

In P atom, the 3d subshell has a lower energy level than the 4s subshell. When P (1s2 2s2 2p6 3s2 3px1 3py1 3pz1) atom is excited, one of the 3s electrons will promote to 3d orbitals, and the electronic configuration becomes 1s2 2s2 2p6 3s1 3px1 3py1 3pz1 4s1. The five half-filled valence orbitals are hybridized to give five sp3d orbitals.



2007-03-20 23:51:10 補充：
Subshells 間的 energy levels 高低與能量相差多少，各原子都不同。以氫為例，energy levels :1s 4s。由於 Ar 或以前的原子 (ground state)，3d 與 4s 都不會填入電子，所以它們的 energy levels 高低，很少提及，避免混亂。但此舉卻引起另一些混亂。

2007-03-20 23:53:41 補充：
打錯字，最尾的紅色字應是 1s2 2s2 2p6 3s1 3px1 3py1 3pz1 3d1 (不是4s1)。

2007-03-20 23:55:47 補充：
以氫為例，energy levels :.......4s = 4p = 4d = 4s3s = 3p = 3d2s = 2p1s

2007-03-20 23:56:21 補充：
以氫為例，energy levels :.......4s = 4p = 4d = 4f3s = 3p = 3d2s = 2p1s