1. Orbital Notation & Electron Configuration
GPS Standards: SC3. Students will use the modern atomic theory to explain the characteristics of atoms. b. Use the orbital configuration of neutral atoms to explain its effect on the atom’s chemical properties
8/30/12

2. the boxes are in order of increasing energy for each sublevel.
orbital notation = a way of showing which orbitals an atom’s electrons are spinning in.
the boxes are in order of increasing energy for each sublevel.
All “s” sublevels hold a total of 2 electrons.
All “p” sublevels hold a total of 6 electrons.
All “d” sublevels hold a total of 10 electrons.
All “f” sublevels hold a total of 14 electrons.
remember:
The Aufbau Principle states that an electron will occupy the lowest-energy orbital that can receive it (start from the left, don’t skip any boxes).
Hund’s Rule states that all same-energy orbitals must be filled by 1 electron each before any electron can pair up within an orbital (like kids on a bus). 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 5d 6p 7s 1s

3. therefore, in order to fill an orbital notation diagram, all you have to do is fill in the boxes (from the beginning) with electrons (2 in each box) until you run out of electrons. By seeing where your last few electrons lie, you will be able to predict the chemical properties of that element. Let’s practice:
Al =
S =
Rh =
Dy =
counting out electrons can get a little cumbersome when you have a lot of electrons to count, but there is an easier way! 1s 2s 2p 3s 3p 1s 2s 2p 3s 3p 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f

4. Sublevels found on the Periodic Table
use this diagram to determine the sublevel your last few electrons are spinning in.
locate your element on the PT
count elements from the left hand side of the sublevel block until you reach your element
draw that number of electrons in the sublevel for your element
fill in all boxes that came before the last sublevel with 2 e- each.
Nd =
Sr =
Sb = 1s
2s p
3s p
4s d p
5s d p
6s d p
7s d 4f 5f
Sublevels found on the Periodic Table 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f 1s 2s 2p 3s 3p 4s 3d 4p 5s 4d 5p 6s 4f

5. Electron Configuration is very similar to orbital notation
Electron Configuration is very similar to orbital notation. Both show the position of all the electrons within the atoms of an element.
electron configuration = a shorter form of ON, using superscripts (instead of boxes and arrows) to show how many electrons occupy each sublevel. Adding the superscripts = the total number of e-. Below is the general order for EC:
1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f146d10
notice how the general order above is in the exact same order you would get if you “read” the periodic table from left to right (see PT sublevel diagram).
Let’s practice:
Al = ___________________
Mo = ____________________________
Bi = _____________________________________________
Er = ________________________________________________

6. 1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p67s25f146d10
Let’s practice:
Al = ___________________
Mo = ____________________________________
Bi = _____________________________________________
Er = ________________________________________________
1s22s22p63s23p 1
1s22s22p63s23p64s23d104p65s24d 4
1s22s22p63s23p64s23d104p65s24d105p66s24f145d106p 3
1s22s22p63s23p64s23d104p65s24d105p66s24f 12 1s
2s p
3s p
4s d p
5s d p
6s d p
7s d 4f 5f

7. there is another way to write the EC of an element—Noble Gas EC.
the noble gases are the elements located in the last column on the PT.
because of their position, they are the only elements whose last energy level is “full” (i.e. Ne has full 2s and p sublevels, for a total of 8 e-).
we can use this information about the noble gases to shorten our EC.
noble gas electron configuration = a short-hand form of EC using a noble gas symbol in brackets. Here’s how do you do it:
locate your element on the PT, then look for the noble gas whose atomic number is closest to your element’s atomic number without going over. Write this noble gases’ symbol in brackets.
the portion of the EC that the noble gas represents no longer has to be written, only what comes after it. 2 He 10 Ne 18 Ar 36 Kr 54 Xe 86 Rn

8. this is the portion of the EC represented by Kr because Kr ends in 4p6
the portion of the EC that the noble gas represents no longer has to be written, only what comes after it.
example: EC and noble gas EC for tin (Sn):
EC = 1s22s22p63s23p64s23d104p6 5s24d105p2
noble gas EC = [Kr]5s24d105p2
Let’s practice:
Al = [___]____________ Re = [___]____________
Mo = [___]____________ K = [___]____________
Bi = [___]____________ Cl = [___]____________
Er = [___]____________ Pr = [___]____________
Now you’re ready for....
you guessed it.....
a FUNSHEET!!!
this is the portion of the EC represented by Kr because Kr ends in 4p6 Ne
3s23p1 Xe
6s2
4f14
5d5 Kr
5s24d4 Ar
4s1 Xe
6s24f145d106p3 Ne
3s2
3p5 Xe
6s24f12 Xe
6s2
4f3