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Chemistry Forums for Students => Inorganic Chemistry Forum => Topic started by: Mitch on February 10, 2006, 04:18:07 AM

Title: Why does Zinc have a lower 2nd ionization energy than Cupper?
Post by: Mitch on February 10, 2006, 04:18:07 AM

Why does Zinc have a lower 2nd ionization energy than Cupper? From simple Zeff considerations you would expect it to be higher.

Title: Re:Why does Zinc have a lower 2nd ionization energy than Cupper?
Post by: Winga on February 10, 2006, 04:55:31 AM

Cu
1st: remove one 4s e-
2nd: remove one 3d e-

Zn
1st: remove one 4s e-
2nd: remove one 4s e-

For Cu 2nd ionization, you need to remove one e- from full-filled 3d-orbitals.

Title: Re:Why does Zinc have a lower 2nd ionization energy than Cupper?
Post by: Mitch on February 10, 2006, 09:51:13 PM

 Is there any good reason why the second electron removed from Zinc is a d-electron?

Title: Re:Why does Zinc have a lower 2nd ionization energy than Cupper?
Post by: Winga on February 10, 2006, 09:55:45 PM

s-electron is more penetrating to the nucleus than d-electron?

Title: Re:Why does Zinc have a lower 2nd ionization energy than Cupper?
Post by: Mitch on February 10, 2006, 09:58:02 PM

I was always under the impression the 3d spends more time near the nucleus than the 4s electron does.

Title: Re:Why does Zinc have a lower 2nd ionization energy than Cupper?
Post by: Winga on February 10, 2006, 10:13:36 PM

Is it true that a 3d-electron is removed in 2nd ionization of zinc.

Title: Re:Why does Zinc have a lower 2nd ionization energy than Cupper?
Post by: Mitch on February 10, 2006, 10:18:59 PM

Isn't that what you said?

Title: Re:Why does Zinc have a lower 2nd ionization energy than Cupper?
Post by: Winga on February 11, 2006, 12:00:51 AM

I said the 3d-orbitals of Zinc will remain full-filled after 2nd ionization originally, but you want a reason for removing 3d e- rather than 4s e-.

I am confused now!

Title: Re:Why does Zinc have a lower 2nd ionization energy than Cupper?
Post by: Mitch on February 11, 2006, 12:05:59 AM

Quote

Cu
1st: remove one 4s e-
2nd: remove one 3d e-

You said it would remove a 3de- first?

Title: Re:Why does Zinc have a lower 2nd ionization energy than Cupper?
Post by: Winga on February 11, 2006, 12:21:26 AM

Because this is copper.

Cu: [Ar]3d¹⁰4s¹

Title: Re:Why does Zinc have a lower 2nd ionization energy than Cupper?
Post by: Mitch on February 11, 2006, 03:29:12 AM

So wait, what's the answer? :P

Title: Re:Why does Zinc have a lower 2nd ionization energy than Cupper?
Post by: Winga on February 11, 2006, 05:18:52 AM

Cu: [Ar]3d¹⁰4s¹

1st I.E. is relatively small (one 4s e- is removed)
2nd I.E. is relatively large (one 3d e- is removed from full-filled 3d-orbitals, extra E is required)

Zn: [Ar]3d¹⁰4s²
1st I.E. is relatively large (one 4s e- is removed from full-filled 4s-orbital, Zeff also increases from Cu to Zn)
2nd I.E. is relatively small (another 4s e- is removed to achieve all full-filled orbitals, relatively stable)