Electron Configuration Packet
Part 1: Understanding the Orbitals
1. What is the shape of an s orbital?
2. What is the relationship between
size of an s orbital and the principal
level in
which it is found?
the
energy
3. What is the shape of a p orbital?
many p orbitals are there in a
sublevel?
How
4. How many electrons can each
hold?
orbital
5. Look at the diagrams of the p
orbitals. What do x, y, and z refer to?
6. How many d orbitals are there in a given sublevel? How many total electrons can the d orbitals in a sublevel hold?
7. Do all the d orbitals have the same shape?
Part 2:Understanding the electron configuration filling
The electrons in an atom occupy distinct principalenergy levels (n). To be located in any
of these principal energy levels, electrons must have the required energy for the level. The
principal energy levels are numbered 1, 2, 3, 4, 5, 6, and 7 for the atoms of the known
elements.
Each principal energy level is subdivided into sublevels. Each sublevel has its own energy
requirement for electrons. The sublevels are labeled s, p, d, and f.
Within each sublevel there is a specific number of orbitals. The orbitals within a given
sublevel have the same energy requirements for electrons. Each orbital can “hold” a
maximum of two (2) electrons.
Rules for “filling” energy levels:
1. Pauli Exclusion Principle: one atomic orbital can accommodate no more than two
electrons, and these electrons must have opposing spins.
2. Hunds Rule: Within a group of orbitals of identical energy (i.e all the 2p orbitals),
electrons enter empty orbitals whenever possible before being paired up.
3. Aufbau principle: How the electrons fill the orbitals. “Build up of energy levels.” 1s,
2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, etc.
Starting with the 1s sublevel, list out the first 15 sublevels in order of increasing energy.
The first few are written for you.
1s ,2s, 2p, _____, _____, _____, _____, _____, _____, _____, _____, _____, _____, _____, ____
Part 3: Electron configurations can be written out by showing the name of the sublevel
(ex: 5d) and writing in the number of electrons in that level as a superscript (ex: 5d7).
**Note: The sublevels are always listed in order of increasing energy.**
1.) Draw in the electrons for silicon.
Orbital Box Diagrams:
1s
2s
2p
3s
3p
Electron configuration for silicon can be written: 1s2, 2s2, 2p6, 3s2, 3p2
Complete the electron configurations for the following elements.
2.) Magnesium:
Total Number of Electrons:________ Valence electrons: _________
Electron Configuration:
3.) Phosphorus:
Total Number of Electrons:________ Valence electrons: _________
Electron Configuration:
4.) Aluminum:
Total Number of Electrons:________ Valence electrons: _________
Electron Configuration:
5.) Selenium:
Total Number of Electrons:________ Valence electrons: _________
Electron Configuration:
6.) Sodium:
Total Number of Electrons:________ Valence electrons: ________
Electron Configuration:
7.) Potassium:
Total Number of Electrons:________ Valence electrons: _________
Electron Configuration:
8.) Carbon:
Total Number of Electrons:________ Valence electrons: _________
Electron Configuration:
9.) Cl- :
Total Number of Electrons:________ Valence electrons: _________
Electron Configuration:
10.)
Mg2+ :
Total Number of Electrons:________ Valence electrons: _________
Electron Configuration:
11.)
N3- :
Total Number of Electrons:________ Valence electrons: _________
Electron Configuration:
Part 4: Valence Electrons
Electrons in the outermost occupied energy shell are called valence electrons. For this
class, only s and p electrons in the outer shell will be counted as valence electrons. After
each element, tell the number of valence electrons it has.
1.) Lithium: ________________________________________________________
___________
2.) Nitrogen:_________________________________________________________
___________
3.) Aluminum:______________________________________________________
___________
4.) Argon:___________________________________________________________
___________
5.) Titanium:__1s2, 2s2, 2p6, 3s2, 3p6 4s2, 3d2______________________
_____2_____
6.) Bromine:_________________________________________________________
___________
Part 5: The Noble Gasses
Draw and then write the electron configurations for each of these (the noble gasses.)
1.) Helium: ________________________________________________________________________
2.) Neon:__________________________________________________________________________
3.) Argon:_________________________________________________________________________
4.) Krypton:______________________________________________________________________
5.) Xenon:_______________________________________________________________________
How are these electron configurations similar?
Noble Gas Notation
You have already seen that an atom with a completely filled energy level is a noble gas. We
can summarize the core electrons in the configurations above by writing the symbol for the
noble gas that has that configuration. Give the noble gas configurations for the following
elements you used in part 4:
1.) Lithium: __________________________________________________________
2.) Nitrogen:___________________________________________________________
3.) Aluminum:_________________________________________________________
4.) Argon:______________________________________________________________
5.) Titanium:___[Ar] 4s2, 3d2____________________________________________
6.) Bromine:____________________________________________________________
Part 6: Ions
1.) Lewis Dot Symbols are drawn to represent the number of valence electrons that an atom has.
One dot is placed on each side of the atom before pairing up the dots. Complete a Lewis Dot
symbol for each of the following elements:
N
F
Ca
B
K
C
Ne
2.) Having a completely filled outer energy shell (8 electrons) is very stable. Elements with
partially-filled valence shells can try to reach a full shell by gaining or losing electrons. In
the table below, give the number of valence electrons, whether elements in this group would
most likely lose or gain electrons, how many, and what charge the elements would then have.
Group
1
2
13
14
15
16
17
18
# Valence e-
Lose/ gain how many electrons?
Charge