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Review
Review of Electron Configurations
Historically, the properties of elements and the way those elements combined with other
elements were the basis for the development of the periodic table (particularly the short
form in the latter half of the 19th century). When physicists developed an understanding
of how atoms were constructed (particularly the configuration of the electrons), it was
possible to relate that structure to the periodic table (particularly the long form). Our
next lesson (Bonding) will emphasize how the electron configurations dictate the chemical
properties and combining patterns of the elements.
| For now let’s focus on how electron configurations are related to the
shape of the periodic table. To begin, I would like you to take a moment to write out the
complete electron configuration for these three elements: hydrogen, lithium and sodium.
Hydrogen has one electron. Lithium has three electrons. Sodium has eleven electrons. So
take a moment to do that before continuing on. |
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Answers
| These are the electron configurations you should have. Notice that
these three elements are all in group Ia of the periodic table. Notice also that each of
those electron configurations ends in s1. It is a different s1 for
each element--it is 1s1 for hydrogen, 2s1 for lithium, and 3s1
for sodium--but notice the similarity in that they all end in s1. |
| H |
1 |
1s1 |
| Li |
3 |
1s22s1 |
| Na |
11 |
1s22s22p63s1 |
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Electron Configuration and the Periodic Table
Now take a look at the periodic table shown below. (A similar table is shown in example
2 in your workbook.) It is another periodic table, but instead of having atomic weights it
has the last part of the electron configuration for each of the elements.
| Periodic Table with Partial Electron
Configurations |
H
1s1 |
|
He
1s2 |
Li
2s1 |
Be
2s2 |
|
B
2s22p1 |
C
2s22p2 |
N
2s22p3 |
O
2s22p4 |
F
2s22p5 |
Ne
2s22p6 |
Na
3s1 |
Mg
3s2 |
Al
3s23p1 |
Si
3s23p2 |
P
3s23p3 |
S
3s23p4 |
Cl
3s23p5 |
Ar
3s23p6 |
K
4s1 |
Ca
4s2 |
Sc
4s23d1 |
Ti
4s23d2 |
V
4s23d3 |
Cr
4s13d5 |
Mn
4s23d5 |
Fe
4s23d6 |
Co
4s23d7 |
Ni
4s23d8 |
Cu
4s13d10 |
Zn
4s23d10 |
Ga
4s24p1 |
Ge
4s24p2 |
As
4s24p3 |
Se
4s24p4 |
Br
4s24p5 |
Kr
4s24p6 |
Rb
5s1 |
Sr
5s2 |
Y
5s24d1 |
Zr
5s24d2 |
Nb
5s14d4 |
Mo
5s14d5 |
Tc
5s24d5 |
Ru
5s14d7 |
Rh
5s14d8 |
Pd
4d10 |
Ag
5s14d10 |
Cd
5s24d10 |
In
5s25p1 |
Sn
5s25p2 |
Sb
5s25p3 |
Te
5s25p4 |
I
5s25p5 |
Xe
5s25p6 |
Cs
6s1 |
Ba
6s2 |
La*
6s25d1 |
Hf
6s25d2 |
Ta
6s25d3 |
W
6s25d4 |
Re
6s25d5 |
Os
6s25d6 |
Ir
6s25d7 |
Pt
6s15d9 |
Au
6s15d10 |
Hg
6s25d10 |
Tl
6s26p1 |
Pb
6s26p2 |
Bi
6s26p3 |
Po
6s26p4 |
At
6s26p5 |
Rn
6s26p6 |
Fr
7s1 |
Ra
7s2 |
Ac§
7s26d1 |
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* |
Ce |
Pr |
Nd |
Pm |
Sm |
Eu |
Gd |
Tb |
Dy |
Ho |
Er |
Tm |
Yb |
Lu |
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| § |
Th |
Pa |
U |
Np |
Pu |
Am |
Cm |
Bk |
Cf |
Es |
Fm |
Md |
No |
Lr |
In the remaining pages of this section, we will take a closer look at the electron
configurations of various groups in the periodic table, look at some short cuts for
determining electron configurations, and look at how atomic orbitals are related to the
periodic table. |
