why my answer is wrong? --- remove electron from orbital

[zhen]

question:
In forming Ni+ and Ni2+, the nickel atom loses electrons from which orbital(s)?

I looked at the periodic tale, and Ni is in the middle, where the 3d orbital located. so when you need to remove one or two electrons, you should remove from the 3d orbital. but that is not right?

the answer for that is 4s instead of 3d orbital. i don't get it. the 3d should have higher energy than 4s, so how can you remove the 4s, but not 3d first?

[Unco]

G"day, Zhen.

As the names indicate, 4s electrons are one energy level higher than the 3d electrons. The 4s electrons are furthest from the nucleus (and have lower energy levels shielding) so require the least amount of energy to remove.

[GCT]

this may help

http://www.webelements.com/webelements/elements/text/Ni/econ.html

[zhen]

G"day, Zhen.
As the names indicate, 4s electrons are one energy level higher than the 3d electrons. The 4s electrons are furthest from the nucleus (and have lower energy levels shielding) so require the least amount of energy to remove.

But the electron configuration of Ni is [Ar] 4s2, 3d8, shouldn't you remove the electron from the 3d8 first? Even though youn sounds right, I still have a little confusion.

[zhen]

this may help
http://www.webelements.com/webelements/elements/text/Ni/econ.html
In my text book, it shows difference configuration.
When I remove two electrons from the picture in the website, it sitll removed the 3d first, and left the 4s untouch.
anyway, thanks for the help.

[Unco]

But the electron configuration of Ni is [Ar] 4s2, 3d8, shouldn't you remove the electron from the 3d8 first? Even though youn sounds right, I still have a little confusion.
We write it [Ar] 3d8 4s2
(albeit with superscripts)

The d orbitals are "late fillers". By "fill" I refer to the number of electrons increasing as you go across the periodic table.

Look at your periodic table:
Ca doesn't have any 3d electrons but has two 4s electrons. It's not until you get to Sc that an electron fills the 3d subshell.

So in that sense, the 4s electrons fill before the 3d electrons. But the 3d subshell is part of the n=3 energy level, and is "below" the 4s subshell.

This most certainly will be discussed in your textbook.

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General question (I'm new): is there a way to prevent formatting (ie. line breaks) from disappearing upon previewing?

[zhen]

thanks very much, i am really appriciated.