common atoms 1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10
Cu & Cr 1s2, 2s2, 2p6, 3s2, 3p6, 4s1, ......
2007-07-04 04:54:44 · 3 answers · asked by high-lighter 3 in Science & Mathematics ➔ Chemistry
because of the big size of the of the 3d shell, when it is completely full, it is energetically very favorable, and as a results slightly shrinks, making the whole atom even more stable. although it is filled after the 4s shell, is still is a shell with n=3, i.e. an internal one.
therefore both Cr and Cu aim at such a d10 configuration, scarifying their 4s shell for it.
2007-07-04 05:13:01 · answer #1 · answered by chem_freak 5 · 1⤊ 0⤋
When filling atomic orbitals it is important to remember that the most stable orbitals are either 1/2 full or completely full. So for Chromium, if you put 2e into the 4s orbital, you then put 4e into the 3d orbital. You end up with one full orbital and one partially (but not half) filled orbital.
So instead, 1e from the 4s orbital "jumps" up to the 3d orbital. In this case, you have one half-filled orbital (4s1) and one more half-filled orbital (3d5). This is a more stable configuration.
In the case of copper, 4s2, 3d9 is less stable than 4s1, 3d10 (one half filled and one filled).
2007-07-04 12:15:59 · answer #2 · answered by Lord B. 1 · 1⤊ 0⤋
Half filled and full filled orbitals are more stable.
2007-07-04 12:04:26 · answer #3 · answered by ag_iitkgp 7 · 2⤊ 0⤋