Chapter 8
SUGGESTED HOMEWORK PROBLEMS
41, 43, 45, 47, 51, 53, 61, 65, 67, 69, 73,
75, 79, 81, 85, 87, 89
Chapter 8
Atomic “zoning rule”:
Pauli exclusion principle – no two electrons may
have the same four quantum numbers.
Electron configurations and orbital diagrams. We
will do from periodic table. (Aufbau principle).
Electron Configs & Orbital
Diagrams
• H – one electron.
• Must go in the lowest energy level available.
(Aufbau)
• n = 1, l = 0, ml = 0, and ms = +1/2 or -1/2
• Choose +1/2
• So l = 0 and ml = 0
• Electron config.:
1s1
• Orbital diagram:
↑
ml = 0
Electron Configs & Orbital
Diagrams
• He – two electrons. First electron has n =
1, l = 0, ml = 0, and ms = +1/2 – same as H
• Second electron: n =
• So l = and ml =
• Since these numbers the same as first
electron, ms must = -1/2 (Pauli)
• Electron config.:
• Orbital diagram:
Electron Configs & Orbital
Diagrams
• Li – three electrons. Electron config is
1s22s1
• Why??? Why not 1s3?
• Try n = 1 for third electron.l = 0 and ml = 0
• First electron: n = 1, l = 0, ml = 0, ms =+1/2
• 2nd electron: n = 1, l = 0, ml = 0, ms = -1/2
• Third electron: n = 1, l = 0, ml = 0, ms =
must be either +1/2 or -1/2 There’s Mr.
Pauli! So...
Electron Configs & Orbital
Diagrams
• Third electron on Li: n = 2
• l = 0, 1, ..., n -1 and n -1 = 1 So l can be or
Choose lowest: l =
• Since l = , ml = Choose ms = +1/2
• Electron config:
• Orbital diagram:
Electron Configs & Orbital
Diagrams
• Be – four electrons. First three same as
Li
• Fourth electron – n =
• l=
;ml =
• ms must be
• Electron config:
• Orbital diagram:
Electron Configs & Orbital
Diagrams
• B – five electrons. First four same as Be
• Fifth electron still n = 2
• Try l = 0, so ml = 0. So ms either +1/2 or 1/2
• Either way, two electrons with same four
Q.N.
• So...
Electron Configs & Orbital
Diagrams
• The fifth electron for B must have quantum
numbers:
• n= ,l=
• ml can range from -l to +l ... choose -1
• ms either +1/2 or -1/2 ... choose +1/2
• Electron config:
• Orbital diagram
Electron Configs & Orbital
Diagrams
• C – six electrons. First five same as B
• Sixth electron: n =
• l = . For l = 1, ml = -1, 0, +1. But -1 already
used. So choose ml =
.
• Hund’s rule: Subshells half fill each orbital
before any are completely filled.
• ms =
• electron config.:
• Orbital diagram:
Electron Configs & Orbital
Diagrams
• N – seven electrons. First six same as C
• Seventh electron – n = 2
• l = 1; ml, already used -1 & 0, so use ml =
• ms=
• Electron config.:
• Orbital diagram:
Electron Configs & Orbital
Diagrams
• O – Eight electrons. First seven same as
N
• 8th electron: n =
• l = 1; ml = -1, 0, +1. Choose ml = -1
• ms must be
• Electron config.:
• Orbital diagram:
Electron Configs & Orbital
Diagrams
• F – nine electrons – first eight same as O
• 9th electron – n =
• l = 1; ml may be 0 or +1 (Hund)
Choose ml = 0
• ms=
• Electron config.;
• Orbital diagram:
Electron Configs & Orbital
Diagrams
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Ne – ten electrons. First nine same as F
10th electron – n =
l = 1; ml must be +1
ms=
Electron config.:
Orbital diagram
Electron Configs & Orbital
Diagrams
•
•
•
•
•
•
•
Third row same as last, with n = 3.
Fourth row: K – 19 electrons.
First 18 electrons same as Ar
19th electron: n = 4; l = 0, 1, or 2...choose l = 0
ml = 0 and ms = +1/2
Electron config.:
or
Orbital diagram: ↑
Electron Configs & Orbital
Diagrams
• Ca – 20 electrons. First 19 same as K
• n = 4; l = 0; ml = 0; ms = -1/2
• Electron config.:
or
• Orbital diagram:
Electron Configs & Orbital
Diagrams
• When we get to Sc, we need to remember that
we haven’t completed the n = 3 quantum
number yet.
• On the third row, we did l = 0 (s subshell) and l =
1 (p subshell).
• But for n = 3, there are three subshells, because
l = 0, 1, ... n - 1 and with n = 3, those are l = 0, 1,
2.
• It is after n = 4, l = 0 (after Ca) that the n = 3, l =
2 (beginning with Sc) starts to fill.
Electron Configs & Orbital
Diagrams
• Sc – 21 electrons. First 20 same as Ca
• 21st electron. Watch out!
• n = ; for n = 3, l = 0, 1, 2. Used l = 0, 1 in row
three. Use l =
• For l = 2 , ml =
...choose ml = -2
ms=
• Elec. config.:
or
•
• Orbital diagram:
Electron Configs & Orbital
Diagrams
• Ti – 22 electrons. First 21 same as Sc
• 22nd electron – n = 3; l = 2;
• ml = -1, 0, +1, +2 (already used -2 – Hund)
Choose ml = -1 ms= +1/2
• Elec. config.:
or
•
• Orbital diagram:
Electron Configs & Orbital
Diagrams
• V – 23 electrons. First 22 same as Ti
• 23rd electron – n = 3; l = 2;
• ml = 0, +1, +2 (already used -2, -1 Hund)
Choose ml = 0 ms= +1/2
• Elec. config.:
or
• Orbital diagram:
Electron Configs & Orbital
Diagrams
• Cr – 24 electrons. First 23 same as V
• 24th electron – n = 3; l = 2;
• ml= +1, +2 (already used -2, -1, 0 – Hund)
Choose ml = +1 and ms= +1/2
• Elec. config.: 1s22s22p63s23p64s23d4 or
[Ar]4s23d4
• Orbital diagram: ↑↓ ↑ ↑ ↑ ↑
• NOT QUITE!!!...SORRY.
Electron Configs & Orbital
Diagrams
•
•
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Cr – 24 electrons. First 23 same as V
24th electron – n = 3; l = 2;
ml = +2 and ms= +1/2
HALF (OR COMPLETELY) FILLED
SUBSHELLS MORE STABLE
• Elec. config.:
• Orbital diagram:
or
Electron Configs & Orbital
Diagrams
•
•
•
•
•
•
Mn – 25 electrons. First 24 same as Cr
25th electron – n = 4; l = 0;
ml = 0; ms = -1/2
Elec. config.:
or
Orbital diagram:
Electron Configs & Orbital
Diagrams
•
•
•
•
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Fe – 26 electrons. First 25 same as Mn
26th electron – n = 3; l = 2;
ml = -2, -1, 0, +1, +2...choose ml = -2
ms= -1/2
Elec. config.:
or
• Orbital diagram:
Electron Configs & Orbital
Diagrams
• Ni – 28 electrons. First 27 same as Co
• 28th electron – n = 3; l = 2;
• ml = 0, +1, +2...(already used -2, -1) choose ml =
0
• ms= -1/2
• Elec. config.:
or
Orbital diagram:
Electron Configs & Orbital
Diagrams
• Cu – 29 electrons. First 28 same as Ni
• 29th electron – n = 3; l = 2;
• ml = +1, +2...(already used -2, -1, 0) choose ml =
+1
• ms= -1/2
• Elec. config.: 1s22s22p63s23p64s23d9 or
[Ar] 4s23d9
• Orbital diagram:
• NO...THERE’S THAT RULE AGAIN
Electron Configs & Orbital
Diagrams
•
•
•
•
•
Cu – 29 electrons. First 28 same as Ni
29th electron – n = 3; l = 2;
choose ml = +2
ms= -1/2
Elec. config.:
or
Orbital diagram:
Electron Configs & Orbital
Diagrams
•
•
•
•
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Zn – 30 electrons. First 29 same as Ni
30th electron – n = 3; l = 2
Complete 4s and 3d subshells
ms= -1/2
Elec. config.:
or
[Ar] Orbital diagram:
Chapter 8
• A summary
1
2
3
4
5
6
H He
1 2
SS
1 2
S S
1 S2 3d
S 2
1 4d
S S
1 2 5d
SS
1 2 3 4 5 6
PP P P P P
1 2 3 4 5 6
PP PP PP
1 2 3 4 5 6
P P P P PP
1 2 3 4 5 6
P P PP P P
1 2 3 4 5 6
PP PP PP
These elements end with s electrons
These elements end with p electrons
These elements end with d electrons
Chapter 8
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• Electron configs and orbital diagrams of ions.
Rule: Metals lose electrons
Which electrons?
The HIGHEST energy electrons are ALWAYS
lost first.
Rule: Nonmetals gain electrons
Where do the electrons go?
Into the LOWEST energy levels available.
Chapter 8
• Li – a metal so it will lose electron(s) to form Li+
• How many?
• Column IA, so one.
ELECTRON CONFIGURATION: 1s2 2s1
ORBITAL DIAGRAM:
The ion:
2
0
ELECTRON CONFIGURATION: 1s 2s
ORBITAL DIAGRAM:
Chapter 8
• Be
• Column IIA – two lost to form Be 2+
The atom:
ELECTRON CONFIGURATION: 1s2 2s2
ORBITAL DIAGRAM:
The ion:
2
0
ELECTRON CONFIGURATION: 1s 2s
ORBITAL DIAGRAM:
Chapter 8
• B
• Column IIIA – three lost to form B3+
The atom:
ELECTRON CONFIGURATION: 1s2 2s2 2p1
ORBITAL DIAGRAM:
The ion:
2
0
0
ELECTRON CONFIGURATION: 1s 2s 2p
ORBITAL DIAGRAM:
Chapter 8
• F
• Column VIIA – one gained to form F-
The atom:
2
2
5
ELECTRON CONFIGURATION: 1s 2s 2p
ORBITAL DIAGRAM:
The ion:
2
2
6
ELECTRON CONFIGURATION: 1s 2s 2p
ORBITAL DIAGRAM:
Chapter 8
• O
• Column VIA – two gained to form O2-
The atom:
ELECTRON CONFIGURATION: 1s2 2s2 2p4
ORBITAL DIAGRAM:
The ion:
2
2
6
ELECTRON CONFIGURATION: 1s 2s 2p
ORBITAL DIAGRAM:
Chapter 8
• N
• Column VA – three gained to form N3-
The atom:
2
2
3
ELECTRON CONFIGURATION: 1s 2s 2p
ORBITAL DIAGRAM:
The ion:
2
2
6
ELECTRON CONFIGURATION: 1s 2s 2p
ORBITAL DIAGRAM:
Chapter 8
• Sc
• Remember, HIGHEST energy electrons lost
FIRST.
The atom:
ELECTRON CONFIG. : 1s2 2s22p63s23p64s23d1
ORBITAL DIAGRAM:
Sc
3+
Chapter 8
• Ti
The atom:
ELECTRON CONFIG. : 1s2 2s22p63s23p64s23d2
ORBITAL DIAGRAM:
4+
Ti
Ti
2+
Chapter 8
• V
The atom:
V3+
Chapter 8
• Do Fe, Fe 2+, & Fe 3+, and predict which ion is
more stable
Fe
ELECTRON CONFIG. : 1s2 2s22p63s23p64s23d6
ORBITAL DIAGRAM:
2+
Fe
3+
Fe
Paramagnetism & Diamagnetism
• Pages 355 – 356
• A substance is
paramagnetic when it
has one or more
unpaired electrons
• Diamagnetic – no
unpaired electrons
Chapter 8
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• Atomic Properties
Ionization Potential – the energy needed to
remove an electron from an atom in the gas
phase.
M(g) --> M1+ (g) + 1 eSecond IP: M1+ (g) --> M2+ (g) + 1 eElectron Affinity – the energy released when an
atom in the gas phase gains an electron.
A(g) + 1 e- --> A-(g)
Chapter 8
• Atomic Properties
atomic radius
ionic radius
IP
EA
down
up
up
up
up up down down
Chapter 8
• Atomic Properties
• Important! See page pp. 362 for
exceptions to general trends in IP and EA.
Chapter 8
• Trends in
Ionization
Potential
• In general, IP
goes up across
the table...but not
always. Why?
F
F
O
N
N
C
B
Be
Li
C
Be
B
Li
O
Chapter 8
• Trends in Electron
Affinity
• Same general trend
true for Electron
Affinity
F
F
O
N
C
B
Be
O
C
Li B
Li
He
He Be
N
Chapter 8
• The electron configs. help us understand
the differences
• Metals more easily lose than gain
electrons.
• Opposite true for nonmetals
• Metalloids in the middle
• Noble gases neither lose nor gain
electrons - complete valence shell
Chapter 8
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• Alkali & Alkaline Metals as Reducing Agents
Alkali (group IA) and Alkaline (Group IIA) metals
are
Good reducing agents.
Low IP and so electrons easily lost - reduces
another atom.
2 Na + 2 HOH –> 2 NaOH + H2
Will react with halogens:
2 Na(s) + Cl2 –> 2 NaCl
Chapter 8
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One electron to gain & a high electron affinity
Good oxidizing agents
Will react with metals & hydrogen:
H2 + Cl2 -> 2 HCl
Will react with each other:
Cl2 + Br2 –> 2 ClBr an interhalogen compound
May or may not take electrons from the ion:
Cl2 + 2 Br- –> 2 Cl- + Br2 but:
Br2 + 2 Cl- –> NR