1. Constructing the periodic table
chapter 4 & 11

2. The Periodic Table Arrangement
The periodic table is arranged by orbital diagrams.
Schrodinger gave us equations that describe atomic orbitals. The values we get from those equations are quantum numbers.
We used quantum numbers to build orbital diagrams, we used orbital diagrams to build the periodic table

4. Using the periodic table to determine orbital diagrams
The period relates to the energy level of electrons
Therefore H and He only have electrons in the 1st energy level
Li, Be, B, C ,N ,O ,F and Ne have electrons up to the 2nd energy level

5. You can determine the orbital by the placement
For these elements the last
electron is in the s orbital He Li
for these elements
the last electron is
in the p orbital
For these elements the last
electron is in the d orbital
For the elements the last electron
is in the f orbital

7. Determining the number of electrons in the last energy level
count the number of elements to the left edge of the “section”
For example Al
It is the first element in the 2nd row of p filling elements
The last electron for aluminum will be the first electron possible in the 2nd p

8. Continuing… Al
The last electron will be the first possible in the 2nd p
1 s __
2 s __ p __ __ __
3 s __ p __ __ __ d __ __ __ __ __

9. Condensed electron configuration
long electron configurations are not normally written out because it gets rather repetitive
Instead it is condensed, by starting from the previous Noble gas and adding shells to it.
For example K
1s22s2p63s2p64s1
Instead becomes
[Ar]4s1
This is the same as saying everything that is in Ar (1s22s2p63s2p6) +4s1

10. To Determine the Condensed electron configuration
Start at the previous noble gas (lower atomic number)
Count out every element in order of atomic number to your given
Determine which shell all elements are filling. The number of elements in that shell is your superscript number.

11. For Iron Previous Noble Gas----Ar Count all elements
K Ca Sc Ti V Cr Mn Fe
These fill 4 s
These fill 3 d
So it is
[Ar] 4s23d6 but we should put the energy levels in order
[Ar]3d64s2

12. Lone electron in the 5d or 6 d
Odd exception
Lanthanum’s last electron fills the 5d orbital.
Ce has its last electron fill in the 4f, and the one from 5d (La) jumps to 4f.
The next elements all fill up the 4f until Gadolinium which fills up the 5d again.
A similar “jumping” of one electron occurs with the actinide series

13. Different Periodic Tables
The electron “jumping” is why there are two forms of the periodic table in common usage.
One has lanthanum and actinium in with the d filling elements.
The other has lanthanum and actinium with the f filling elements

15. Homework For the following elements
Ignore the exception if you run into it.
fill in the last shell only of the orbital diagram and do the condensed electron configuration
Ti, Cl, Sr, Sn and Au