Transcript Document

Unit 03
The Modern Atom
Quantum Mechanical Model
• Quantum mechanics was developed by
Erwin Schrodinger
• Estimates the probability of finding an e- in a
certain position
• Electrons are found in an “electron cloud” or
orbital
Orbital (“electron cloud”)
– Region in space where there is 90% probability
of finding an e-
Orbital
Radial Distribution Curve
Each orbital letter has a different shape.
“s” orbital
spherical shaped
1 orbital
“p” orbital
Dumbbell shaped
Arranged x, y, z axes
3 orbitals
“d” orbital
clover shaped
5 orbitals
“f” orbital
7 orbitals
• Orbitals combine to form a
spherical shape.
f
2px
2py
2s
2pz
Hog Hilton
You are the manager of a prestigious new hotel in downtown
Midland—the “Hog Hilton”. It’s just the “snort of the town”
and you want to keep its reputation a cut above all the
other hotels. Your problem is your clientele. They are hogs
in the truest sense.
Your major task is to fill rooms in your hotel. The Hog Hilton
only has stairs. You must fill up your hotel keeping the
following rules in mind:
1) Hogs are lazy, they don’t want to walk up stairs!
2) Hogs want to room by themselves, but they would
rather
room with another hog than walk up more stairs.
3) If hogs are in the same room they will face in opposite
directions.
4) They stink, so you can’t put more than two hogs in each
room.
Hog Hilton
• Your hotel looks like the diagram below:
6th floor ________
5th floor ________ ________ ________
4th floor ________
3rd floor ________ ________ ________
2nd floor ________
1st floor ________
Book 7 hogs into the rooms.
Hog Hilton
Your hotel looks like the diagram below:
6th floor ________
5th floor ________ ________ ________
4th floor ________
3rd floor ________ ________ ________
2nd floor ________
1st floor ________
Book 14 hogs into the rooms.
Hog Hilton
Choose 3 Days of the week and Draw them
in the left side of your spiral.
6th floor ______
5th floor ______ ______ ______
4th floor ______
3rd floor ______ ______ ______
2nd floor ______
1st floor ______
=↑
=↓
Let’s play Hog Hilton!!
Now you will relate the “Hog Hilton” to electron orbitals. Electron
orbitals are modeled by the picture on the left and are grouped into
principal energy levels.
1. Compare their similarities and differences.
2. To go between floors on the Hog Hilton did the hogs need to use
energy? Would electrons need to use the energy to go between
orbitals?
3d ___ ___ ___ ___ ___ n=3
(4s ____) n=4
3p ___ ___ ___ n=3
3s ___ n=3
2p ___ ___ ___ n=2
2s ___ n=2
1s ___ n=1
6th floor ___
5th floor ___ ___ ___
4th floor ___
3rd floor ___ ___ ___
2nd floor ___
1st floor ___
A. Rules for e- configurations
1. Aufbau principle: electrons fill the
lowest energy orbitals first.
(Hogs are lazy, they don’t want to walk up
stairs!)
A. Rules for e- configurations
2. Pauli Exclusion principle: each orbital
can hold TWO electrons with
opposite spins
(They stink, so you can’t put more
than two hogs in each room. & If
hogs are in the same room they will
face in opposite directions.)
A. Rules for e- configurations
3. Hund’s rule: within a sublevel, place one
e- per orbital before pairing them.
(Hogs want to room by themselves, but they
would rather room with another hog than walk
up more stairs.)
WRONG
RIGHT
B. Drawing Orbitals
Krypton
↑↓ ↑↓ ↑ ↓
4p ___ ___ ___
↑↓ ___
↑↓ ___
↑ ↓ ___
↑↓ ___
↑↓
3d ___
4s ↑↓
___
↓ ___
↑↓ ___
↑↓
3p ↑___
3s ↑↓
___
↓ ↑___
↓ ↑___
↓
2p ↑___
↑↓
2s ___
1s ↑↓
___
White Board Practice:
Drawing Orbitals
Chlorine
4p ___ ___ ___
3d ___ ___ ___ ___ ___
4s ___
↓ ___
↑↓ ___
↑
3p ↑___
3s ↑↓
___
↓ ___
↑↓ ___
↑↓
2p ↑___
↑↓
2s ___
1s ↑↓
___
White Board Practice:
Drawing Orbitals
Nickel
4p ___ ___ ___
↑↓ ___
↑↓ ↑___
↓ ↑___↑ ___
3d ___
4s ↑↓
___
↓ ↑___
↓ ↑___
↓
3p ↑___
3s ↑↓
___
↓ ↑___
↓ ↑ ___
↓
2p ↑___
↑↓
2s ___
1s ↑↓
___
C. Writing the Electron Configuration
Krypton: atomic number - 36
4p _ ↑↓ _
3d _ ↑↓ _
4s _ ↑↓ _
3p _ ↑↓ _
3s _ ↑↓ _
2p _ ↑↓ _
2s _ ↑↓ _
1s _↑↓_
_ ↑↓ _ _ ↑↓ _
_ ↑↓ _ _ ↑↓ _ _ ↑↓ _ _ ↑↓ _
_ ↑↓ _ _ ↑↓ _
_ ↑↓ _ _ ↑↓ _
Exponent is number of e-
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
Add the exponents to check your answer
Iron
White Board Practice:
Writing Electron Configurations
Fe – atomic number 26
4p ___ ___ ___
↑↓ ___
↑ ↑___↑___↑ ___
3d ___
4s ↑↓
___
↓ ↑___
↓ ↑___
↓
3p ↑___
3s ↑↓
___
↓ ↑___
↓ ↑ ___
↓
2p ↑___
Add the exponents to check your answer
↑↓
2s ___
2 2s2 2p6 3s2 3p6 4s2 3d6
1s
↑↓
1s ___
White Board Practice:
Writing Electron Configurations
Sulfur
S – atomic number- 16
4p ___ ___ ___
3d ___ ___ ___ ___ ___
4s ___
↓ ↑___↑___
3p ↑___
3s ↑↓
___
↓ ↑___
↓ ↑ ___
↓
2p ↑___
Add the exponents to check your answer
↑↓
2s ___
2 2s2 2p6 3s2 3p4
1s
↑↓
1s ___
Worksheet: Electron Configurations
Aluminum atomic number - 13
1s2 2s2 2p6 3s2 3p1
Al Electron Configuration:___________________
1s 2s
↑↓
↑↓
___ ___
2p
↑↓ ___
↑↓ ___
↑↓
___
3s
↑↓
___
3p
↑ ___ ___
___
11
22
33
4
5
6
7
e- config. Periodic Patterns
s
n = Principle energy level
p
(Period #)
d (n – 1)
f (n – 2)
6
7
What is the electron configuration for Br?
1s2 2s2 2p6 3s2 3p6 4s2 3d104p5
11
22
33
44
55
66
77
Br
What is the electron configuration for
Sulfur?
1s2 2s2 2p6 3s2 3p4
11
22
33
44
55
66
77
S
What is the electron configuration for Titanium?
1s2 2s2 2p6 3s2 3p6 4s2 3d2
11
22
33
44
55
66
77
Ti
What element has the electron configuration
1s22s22p63s23p4?
Add together all the exponents, then find that
atomic number. = Sulfur 16
Learning Check
How many electrons are present in the d sublevel of a
neutral atom of Manganese?
1 2 3 4 5
5 electrons
D. Noble Gases Shorthand
• Use the noble gas in the previous
row.
• Write noble gas symbol in brackets
then rest of the e-configuration.
Longhand Configuration
S 16e- 1s2 2s2 2p6 3s2 3p4
Shorthand Configuration
2
4
S 16e [Ne]3s 3p
Noble Gas Shorthand
Ex – Silicon
11
22
33
44
55
66
77
2
[Ne] 3s
2
3p
Noble Gas Shorthand
• Ex - Germanium
11
22
33
44
55
66
77
2
[Ar] 4s
10
3d
2
4p
Noble Gas Shorthand
• Ex - Cesium
11
22
33
44
55
66
77
1
[Xe]6s
Learning Check
Use Noble Gas Shorthand write the econfig.
1. Cr
[Ar] 4s2 3d4
2. Br
[Ar] 4s2 3d10 4p5
3. Sn
[Kr] 5s2 4d10 5p2
4. Ba
[Xe] 6s2
Learning Check
1. Which orbital quantum number
combination is not possible?
A. 2s
B. 2d
C. 4d
D. 3p
Learning Check
2. How many electrons are required to fill the
1st energy level?
A. 2
B. 4
C. 8
D. 10
Learning Check
3. How many electrons are required to fill the
2nd energy level?
A. 2
B. 4
C. 8
D. 10
Learning Check
4. How many electrons are required to fill the
3rd energy level?
A. 4
B. 8
C. 10
D. 18
Correct orbital filling order
7s
6s
5s
4s
3s
2s
1s
7p
6p
5p
4p
3p
2p
7d
6d
5d
4d
3d
7f
6f
5f
4f
The trick to f orbitals!
Examples:
24f115d1
[Xe]
6s
Erbium- Er 68
Hassium- Hs [Rn] 7s25f146d6
Learning Check
Use Noble Gas Shorthand write the e- config.
1. Sm
[Xe] 6s2 4f5 5d1
2. Db
[Rn] 7s2 5f14 6d3
II. Quantum Numbers
• Four Quantum Numbers:
– Specify the “address” of each electron in an
atom
UPPER LEVEL
II. Quantum Numbers
1. Principal Quantum Number ( n )
– Energy level
– Size of the orbital
– n2 = # of orbitals in
the energy level
II. Quantum Numbers
2. Angular Momentum Quantum # ( l )
– Energy sublevel
– Shape of the orbital
3
2
0
1
s
p
d
f
II. Quantum Numbers
Principal energy
level (n)
Number of
sublevels
Names of Sublevels
1st energy level
1 sublevel
“s” (1 orbital)
2nd
2 sublevels
“s” (1) & “p” (3 orbitals)
3rd
3 sublevels
“s”(1) , “p” (3) & “d” (5 orbitals)
4th
4 sublevels
“s”(1), “p”(3) , “d”(5), and “f” (7)
• n = # of sublevels per level
• n2 = # of orbitals per level
• Sublevel sets: 1 s, 3 p, 5 d, 7 f
II. Quantum Numbers
3. Magnetic Quantum Number ( ml )
– Orientation of orbital
– Specifies the exact orbital
within each sublevel
II. Quantum Numbers
px
py
pz
II. Quantum Numbers
4. Spin Quantum Number ( ms )
– Electron spin  +½ or -½
– An orbital can hold 2 electrons that spin in
opposite directions.
+½
-½
II. Quantum Numbers
– No two electrons in an atom can have the
same 4 quantum numbers.
– Each e- has a unique “address”:
1. Principal #
2. Ang. Mom. #
3. Magnetic #
4. Spin #




energy level
sublevel (s,p,d,f)
orbital
electron
A. Oxidation States
• Valence electrons – the outer electrons in
an atom that are involved in chemical
bonding
• Octet Rule - when forming compounds
atoms want to have 8 e- (s2p6) like the
noble gases (except He)
A. Oxidation States
• A “+” means lose electrons
• A “–” means gains electrons
• Determine the element’s behavior in the
company of other elements
• Some elements only have one oxidation
state, others have several
• The transition metals generally have
several oxidation states
B. Justifying Oxidation States
• Metals lose e- to either minimize e- to e- repulsions
or eliminative their valence e- entirely
• Nonmetals tend to gain electrons to acquire an
octet of electrons
– (8 valence e- arranged as ns2np6 where n = principle
energy level)
– Noble gases have octet naturally
• Transition metals have oxidation state of +2 since
they lose the s2 that was filled just before the dsublevel began filling
• 3d e- are similar in energy to 4s e- & 4d are similar
to 5s, etc.
B. Justifying Oxidation States
Example 1:
Sulfur have many oxidation states. Use an
orbital notation to justify its most common
-2 oxidation state:
[Ne]
↑↓ 3p ___
↑↓ ↑___ ___
↑
3s ___
Sulfur is a nonmetal and tends to gain ecreating the -2 charge. Gaining 2 e- gives
it an octet of 3s23p6.
B. Justifying Oxidation States
Example 2:
Copper has two common oxidation states, +2 and +1.
Justify both oxidation states:
Cu has an ending e- conf. of 4s23d9. Start by drawing its
orbital notation of the outermost, valence electrons.
4s
3d
[Ar] ↑___ ___
↑ ___
↑ ___
↑ ___
↑
↑ ___
↑
↑
↑
↑
↑
Since Cu is a transition metal, the +2 oxidation state
come from losing the 4s e-s leaving 4s03d9.
The +1 oxidation state for Cu come from transferring one
of the s e-s to the d orbitals to fill that sublevel and
then losing the remaining s e- to form 4s03d10.
Recap from yesterday
Principle Energy level – large
number in front
Sublevel – # and letter (orbital)
7s
6s
5s
4s
3s
2s
1s
7p
6p
5p
4p
3p
2p
7d
6d
5d
4d
3d
7f
6f
5f
4f
4p ___ ___ ___
3d ___ ___ ___ ___ ___
4s ___
3p ___ ___ ___
3s ___
2p ___ ___ ___
2s ___
1s ___
4th Principle Energy Level – 4 sublevels
3rd Principle Energy Level – 3 sublevels
2nd Principle Energy Level – 2 sublevels
1st Principle Energy Level – 1 sublevel
s– 1 orbital
p – 3 orbitals
d – 5 orbitals