Re: Need help for painting the periodic table



Wilco Oelen wrote:


The scheme for adding electrons with increasing element number is not
that simple.

For elements 1,2 it is simple. Electrons are added to the first shell.
For elements 3 .. 10 electrons are added to the second shell.
For elements 11 .. 18 electronsare added to the third shell.
Elements 19, 20 (K, Ca) add electrons to the fourth shell.

From this point, however things become more complicated. 
Elements 21, 22, 23 add electrons to the *third* shell, which is one
shell below the outer shell.
Element 24 (Cr) adds *two* electrons to the third shell and *takes* one
from the fourth shell.
Element 25 adds one electron again to the fourth shell.
Eleements 26 up to 30 add electrons to the third shell again.
Elements 31 to 36 again are more well-behaved and add electrons to the
fourth shell.

Shells can have more than 8 electrons. The maximum number of electrons,
a shell can hold can be written as

    SUM(2*(2*i-1)) for i from 1 to N inclusive, with N the shell
number.

For N=1 this gives 2, for N=2, this gives 8, for N=3, this gives 18 and
for N=4 this gives 32. Each value of i stands for a sub-shell, which
can contain 2*(2*i-1) electrons. The number of sub-shells in a shell
with number N equals N.

So at the end of the 3rd row Argon only fills less than half of the third shell? Then Potassium and Calcium start adding to the 4th shell? But Scandium through Zinc ignor the 4th shell instead stuffing additional electrons in the 3rd shell. Then when the 3rd shell is full Gallium again starts adding to the 4th shell.

(Firing up Excel...)
N
5    50
6    72
7    98
8   128

You explanation makes some of the pages Google gives me a little more understandable. Looking at
http://www.corrosionsource.com/handbook/periodic/89.htm
I can see the first three shells are filled up but shells 4 thru 8 still have room for many more electrons.


For the so-called transition elements, the lanthanoids and actinoids,
the pattern of adding electrons is more complex than for the other
elements and one cannot simply say that for each increment in the
element number an electron is added to a certain shell. Electrons can
be added to deeper shells, as shown by the examples above for elements
21 .. 30.

Whether an electron is added to the outer shell, one shell deeper or
even two shells deeper cannot simply be reasoned upon.
Quantum-mechanical computations show that e.g. for chromium (element
24) it is energetically more favorable to have only one electron in its
outer shell and hence, it adds, compared with elements 23 (vanadium)
two electrons to the deeper shell and takes one from the outer shell.
Why this is the case cannot be explained in simple layman terms,
quantum mechanics computations are needed to understand this.

Wilco


I have to confess this is confusing to me --- but very interesting!

I'm still baffled how to color the transition elements. I'll put it another way. The more alkali (electron giving), the cooler the color. the more acidic (electron taking) the warmer the color. It'll be sort of a rainbow with hydrogen, lithium, sodium etc. being on the blue end and the halogens being on the the red end?

Are the transition elements generally less acidic than the IIIA group?

--
Hop David
http://clowder.net/hop/index.html

.

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