“A” students work
(without solutions manual)
~ 10 problems/night.
Alanah Fitch
Flanner Hall 402
508-3119
afitch@luc.edu
Office Hours W – F 2-3 pm
Module # 5
Charge and
Successful
Reactions
Chemistry
General
FITCH Rules
G1: Suzuki is Success
G2. Slow me down
G3. Scientific Knowledge is Referential
G4. Watch out for Red Herrings
G5. Chemists are Lazy
C1. It’s all about charge
C2. Everybody wants to “be like Mike”
C3. Size Matters
C4. Still Waters Run Deep
C5. Alpha Dogs eat first
What do you observe about the circled element?
Followed by an element with much lower abundance
Abundance is related to stability of internal organization of energy
Circled element is more stable
Circled element is Group 18 – Noble Gases
Everyone wants to “be like Mike”
100
10
1
% of solar system elements
0.1
0.01
0.001
0.0001
1E-05
1E-06
1E-07
1E-08
1E-09
1E-10
1E-11
1
6
11
16
21
26
31
36
41
46
51
Z, Number of protons
56
61
66
71
76
81
+1
+2
Losing a few electrons
here let’s these guys
look like this “break”
These guys
can’t “be like
mike” so they
settle
For second or
third best
Mike
+1 to +5 (7)
Losing a few
electrons here
lets these guys
Get ½ a loaf
+1 to +2 (3)
Gaining
Electrons
Makes
Them “be
like Mike”
Also can gain to be like MIke
-1 to -4
2-
1-
Mike
Losing Electrons
Makes them
“be like Mike”
Chemistry
General
FITCH Rules
G1: Suzuki is Success
G2. Slow me down
G3. Scientific Knowledge is Referential
G4. Watch out for Red Herrings
G5. Chemists are Lazy
C1. It’s all about charge
C2. Everybody wants to “be like Mike”
C3. Size Matters
C4. Still Waters Run Deep
C5. Alpha Dogs eat first
Jm
k  8.99 x10
C2
9
Energy electrostatic
r1
It’s all about charge
 q1 q 2 
 k

 d 
Distance between the objects
r2
d
r1  r2
 q1q2 

E el  k 
 r1  r2 
Charge on object 1 or 2, in coulombs
Ionic Charge = 1
7.00E-14
3
4
As Charge increases
The repulsive energy of like charged
Or attractive energy of differently charged
Ions increases
It’s all about charge
+1 charged ions are “losers” compared to more
highly charged ions
6.00E-14
5.00E-14
Electrostatic
ElectrostaticInteraction
InteractionEnergy
Energy(J)
(J)
2
5.00E-14
3.00E-14
4.00E-14
1.00E-14
3.00E-14 0
-1.00E-14
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
2.00E-14
-3.00E-14
1.00E-14
-5.00E-14
0.00E+00
-7.00E-14 0
Radius of ion (pm)
 q1q2 

E el  k 
 r1  r2 
Chemistry
General
FITCH Rules
G1: Suzuki is Success
G2. Slow me down
G3. Scientific Knowledge is Referential
G4. Watch out for Red Herrings
G5. Chemists are Lazy
C1. It’s all about charge
C2. Everybody wants to “be like Mike”
C3. Size Matters
C4. Still Waters Run Deep
C5. Alpha Dogs eat first
7.00E-14
Energy of attraction of differently charged ions
Or energy of repulsion of same charged ions
Decreases
With increasing size of ion
Size Matters
Electrostatic Interaction Energy (J)
5.00E-14
3.00E-14
1.00E-14
-1.00E-14
0
0.02
0.04
0.06
0.08
0.1
0.12
0.14
0.16
0.18
0.2
-3.00E-14
-5.00E-14
-7.00E-14
Radius of ion (pm)
 q1q2 

E el  k 
 r1  r2 
+2
-1 to -4
Mike
+1 to +5 (7)
+1 to +2 (3)
2-
1-
Mike
+1
Who is going to have a strong electrostatic effect?
Transition Elements (+1 to +5) (+1 to +3)
Who is going to have a weak electrostatic effect?
Group 1 cations (+1)
Spectators
Group 17 anions (-1)
“Strong” electrolytes
Who might sometimes win/lose (Intermediate electrostatic effect)?
Group 2 cations (+2) depending on ionic radius
Group 16 anions (-2) depending on ionic radius
Ion
hydrogen
lithium
sodium
potasium
cesium
Symbol
D+
Li+
Na+
K+
Cs+
beryllium Be2+
magnesiumMg2+
calcium
Ca2+
strontium Sr2+
barium
Ba2+
oxide
sulfide
selenide
telluride
fluoride
chloride
bromide
iodine
O2S2Se2Te2FClBrI-
Are there differences in predicted electrostatic effect?
Charge
Radius (pm) Charge/radius
4
1
1 89.66666667
1 127.4285714
1
164
1 192.8333333
2
59
2
85
2
129.5
2 143.3333333
2
149
-2
-2
-2
-2
-1
-1
-1
-1
0.25
0.011152416
0.007847534
0.006097561
0.005185825
0.033898305
0.023529412
0.015444015
0.013953488
0.013422819
H+ should
behave
differently
Be2+ and Mg2+
should behave
differently
124.2 -0.01610306
O2- and, maybe, S2170 -0.011764706 should behave
184 -0.010869565 differently
207 -0.009661836
116.625
167
182
206
-0.008574491
-0.005988024
-0.005494505
-0.004854369
F- should
behave
differently
 q1q2 

E el  k 
 r1  r2 
D+
0.04
Be2+
Charge/(average ionic radius)
0.03
Mg2+
0.02
Li+
0.01
0
-2.5
-2
-1.5
-1
-0.5
F-
0
-0.01
O2 -0.02
Some of the points don’t fall
Within a “cluster”
Charge on ion
0.5
1
1.5
2
2.5
The guys we just saw as “outliers” are at top of
Periodic table
(smaller)
+1
+2
Mike
+1 to +5 (7)
+1 to +2 (3)
2-
Mike
-1 to -4
1-
What about polyatomic ions we memorized?
Who has a strong electrostatic effect?
Weak effect predicted based
On charge
 q1q2 

E el  k 
r

r
 1 2
Strong effect predicted based
On charge
Two main exceptions: OHSO42Why are these exceptions?
http://www.usm.maine.edu/~newton/Chy251_253/Lectures/Resonance/Resonance.html
O
O
S
Na
O
q
ch arg e density 
r
O
O
O
Na
Na
O
“ionic size” = 230 pm
Na
Sulfate
Ionic size = 185 pm
2-
Carbonate 2Sulfate has
Less impact
Than
Carbonate
Even though
It is -2
Most negative part of the molecule
How would you describe this?
Are the negative parts of the molecule
isolated?
Are the negative parts of the molecule at
the edges?
What is q/r for sulfate?
http://www.madsci.org/posts/archives/jan2000/949098457.Ch.r.html
Most negative part of molecule
How would you describe this?
Are the negative parts of the
molecule isolated?
Are the negative parts of the
molecule at the edges?
What is q/r for carbonate?
http://www.lsbu.ac.uk/water/molecule.html
q
ch arg e density 
r
Electron density of water
Shape and charge distribution
On water
Electrons on Oxygen sit
“out there” causing large
Electrostatic potential
Oriented on the electrons
What would happen to the charge if we remove H and leave
Behind electrons to make OH-? Where will those electrons go?
Expect OH- to have highly localized negative charge
What is q/r for OH-?
S2-
No Clean Socks
Cl-
Oh, Card me PleaSe
Electrostatic Effect
1-
1+
2+
Low Charge Density
Strong electrolytes
Bad (stinky) Partners
+1 to +5 (7)
Oh Card me PleaSe
2-
Hi Charge Density
Weak Electrolyte
Good Partners
+1 to +2 (3)
Mike
No Clean Socks
Chemistry
General
FITCH Rules
G1: Suzuki is Success
G2. Slow me down
G3. Scientific Knowledge is Referential
G4. Watch out for Red Herrings
G5. Chemists are Lazy
C1. It’s all about charge
C2. Everybody wants to “be like Mike”
C3. Size Matters
C4. Still Waters Run Deep
C5. Alpha Dogs eat first
“A” students work
(without solutions manual)
~ 10 problems/night.
Alanah Fitch
Flanner Hall 402
508-3119
afitch@luc.edu
Office Hours W – F 2-3 pm