Transcript AP Notes Chapter 8

AP Notes Chapter 7
Electron Configuration
Magnetism
Periodic Trends
Aufbau Principle
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Aufbau is German for building up.
As the protons are added one by one, the
electrons fill up hydrogen-like orbitals.
e- are added to atoms into the lowest
energy level & sub-level available
Fill up in order of energy levels.
Details
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Valence electrons- the electrons in the
outermost energy levels (not d).
Core electrons- the inner electrons.
Hund’s Rule- The lowest energy
configuration for an atom is the one that
will have the maximum number of
unpaired electrons in the orbital.
C 1s2 2s2
2p2
max e
n=1
-
n=1 s
n=2
max e
2
-
n=1 s
n=2 s 2
p 6
n=3
max e
2
8
-
-
n=1 s
n=2 s 2
p 6
n=3 s 2
p 6
d 10
max e =
2
8
18
2
2n
Pauli Exclusion Principle
n
l
1
1
2
2
2
2
2
2
2
2
0
0
0
0
1
1
1
1
1
1
ml
0
0
0
0
-1
-1
0
0
1
1
s
+1/2
-1/2
+1/2
-1/2
+1/2
-1/2
+1/2
-1/2
+1/2
-1/2
Orbital
1S
2s
2p
Pauli Exclusion Principle
2 e- in same atom can
have the same set of four
quantum numbers
 No
Electron Probability
Space &
Quantum Numbers
Quantum #s
___, ___, ___, ___
n 
ml ms
Spin QN = ms (s)
1
ms  
2
-
spin of e on own axis
Increasing energy
7s
6s
5s
7p
6p
5p
4p
4s
1s
5d
5f
4d
4f
3d
3p
Ar with 18 electrons
2p
Ne with 10 electrons
3s
2s
6d
He with 2 electrons
Fill from the bottom up
following the arrows
7s 7p 7d 7f
6s 6p 6d 6f
5s 5p 5d 5f
4s 4p 4d 4f
3s 3p 3d
2s 2p
1s
• 1s2 2s2 2p6 3s2
3p6 4s2 3d10 4p6
5s2 4d10 5p6 6s2
• 38
56electrons
20
4212
7s
6s
5s
4s
3s
2s
1s
7p ...
6p 6d ...
5p 5d 5f ...
4p 4d 4f
3p 3d
2p
Details
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Elements in the same column have the
same electron configuration.
Put in columns because of similar
properties.
Similar properties because of electron
configuration.
Noble gases have filled energy levels.
Transition metals are filling the d orbitals
Examples
3Li
6C
8O
19K
24Cr
29Cu
Exceptions
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Ti = [Ar] 4s2 3d2
V = [Ar] 4s2 3d3
Cr = [Ar] 4s1 3d5
Mn = [Ar] 4s2 3d5
Half filled orbitals.
Scientists aren’t sure of why it happens
same for Cu [Ar] 4s1 3d10
All atoms want a noble gas
or pseudo noble gas
configuration
Atoms with full or half-full
sub-levels are particularly
stable
e
Gain or loss of
produces ions
Consider:
2+
Zn ,
+
Ag ,
2+
Cu
Energy Level Diagram
3d __ __ __ __ __
4s __
3p __ __ __
3s __
2p __ __ __
2s __
1s __
e
Gain or loss of
produces ions
Consider:
2+
Zn ,
+
Ag ,
2+
Cu
Ions with full or half-full
sub-levels are particularly
stable
e
Gain or loss of
produces ions
Consider:
+
Na ,
Ne,
F
Energy Level Diagram
3d __ __ __ __ __
4s __
3p __ __ __
3s __
2p __ __ __
2s __
1s __
e
Gain or loss of
produces ions
Consider:
+
Na ,
Ne,
F
Chemical species with the
same e- configuration are
ISOELECTRONIC
Diamagnetic - Slightly repelled by a
strong magnet (moments counter
each other e- are paired)
Paramagnetic – Attracted to magnetic
field (moments not aligned e- are
unpaired )
Ferromagnetic – Materials retain a
magnetic field if one has been
induced (moments are aligned e- are
unpaired)
Trends
of the
Periodic Table
Triplet Trends
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Organize trends
Use only increasing properties
Learn the diagonal NOT the two vectors
that make up the diagonal…..
You can always recreate the two vectors
so you have less to learn or memorize
Atomic Number
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Increases to the right
Increases down
Atomic Mass
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Increases to the right
Increases down
Nuclear Charge
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Increases to the right
Increases down
Atomic Radius
 Is
taken as the covalent
radius for non-metallic
elements and as the metallic
radius for metals
Atomic Radius
 Covalent
radius is
one-half the
distance between
the nuclei of two
identical atoms
that are singly
bonded to one
another.
Atomic Radius
 Covalent
radii for elements
whose atoms do not bond
to one another can be
estimated by combining
radii of those that do with
the distances between
unlike atoms in various
molecules.
Atomic Radius
 Metallic
radius is one-half
the closest internuclear
distance in a metallic
crystal.
Atomic Radius
Atomic Radius (pm)
200
150
100
50
0
1
3
5
7
9
11 13
Atomic Number
15 17 19
Atomic Radius
Ionic Radii Size
Overall Activity
Ionization Energy
 Is
the energy required to
remove the outermost
electron from an atom or a
positive ion in the ground
state.
First Ionization Energy
 Energy
required to remove
the first electron from a
neutral atom.
First Ionization Energy
1st Ionization Energy (kJ/mol)
2500
2000
1500
1000
500
0
1
3
5
7
9
11
13
Atomic Number
15
17
19
First Ionization Energy
First Ionization Energy
Second Ionization Energy
 Energy
needed to remove
the outermost electron from
a +1 ion.
 Energy needed to remove
the second electron from a
neutral atom.
Second Ionization Energy
2nd Ionization Energy (kJ/mol)
8000
7000
6000
5000
4000
3000
2000
1000
0
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Atomic Number
Electron Affinity
 Energy
released or
absorbed when an electron
is added to the valence level
of a gas-phase atom.
Electron Affinity
100
Electron Affinity (kJ/mol)
50
0
-50
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
-100
-150
-200
-250
-300
-350
-400
Atomic Number
Electron Affinity
Electronegativity
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Ability to bond & desire for electrons