Chemistry, The Central Science, 10th edition
Theodore L. Brown; H. Eugene LeMay, Jr.; and Bruce E. Bursten
Unit 01 (Chp 6,7):
Atoms, Electrons,
& Periodic Properties
John D. Bookstaver
St. Charles Community College
St. Peters, MO
 2006, Prentice Hall, Inc.
Development of Atomic Models
• Indivisible
• Identical
• React in
fixed ratios
• + stuff
• – electrons
• empty
space
+
Rutherford’s atomic
model didn’t explain
properties of matter
(color, reactivity, …)
Li
Na
Cu
white light  continuous spectrum
prism
Atomic Emission Spectra
elements  discrete lines of E & f
helium
(He)
prism
lamp
(only specific colors of
energy & frequency)
Hydrogen Emission Spectrum
A mystery for
Niels Bohr.
Bohr’s Shell Model
(1913–Niels Bohr)
electrons occupy only specific levels (or shells)
of “quantized” energy
(& wavelength & frequency)
Electrons as Waves
quantized into
specific multiples
of
wavelengths,
but none
in between.
Bohr’s Shell Model
EXCITED
state
e–’s absorb
(+) energy,
move to
outer
levels
(n=2 to n=5)
5
2
∆E
e–’s emit
(–) energy,
move back
to inner
levels
(n=5 to n=2)
GROUND
state
4
2
3
2
Which transition shows a light wave
of the greatest energy? n=5 to n=2
Photon Energy as Light Waves
• Distance between same points on adjacent
wavelength () (m)
waves is the _______________.
• Number of Waves passing a given point
frequency () (Hz)(s–1)
per unit time is the ______________.
 and  are
inversely proportional
_________
All light waves
move at the
same speed, so
which color has
more energy?
R
Low
Energy
O
Y
G
B I V
High
Energy
Electromagnetic Spectrum
Low Frequency
High Frequency
(higher E) (higher ) (shorter )
All EM radiation travels at the same speed:
the speed of light (c), 2.998  108 m/s. c = 
Photon (Light) Calculations
Given wavelength () of light, one can
calculate the energy (E) of 1 photon of that light:
2.998  108 m/s
c = 
 ,  (inverse)
↔
(constants)
(given on Exam)
HW p. 253
#14,25ab,26,34
6.626  10–34 J•s
E = h
E ,  (direct)
↔E
Quantum Mechanical Model
(1926–Schrodinger & Others)
Heisenberg Uncertainty Principle:
the more precisely a particle’s
motion is known,
(wave)
the less precisely its
position is known.
(particle)
Schrödinger
Wave Equation:
s,p,d,f
probable 3-D regions (ORBITAL shapes) or
sublevels occupied by electrons in each fixed level.
Development of Atomic Models
1803 Dalton
Atomic Theory
1904 Thomson
Plum Pudding
1911 Rutherford
Nuclear Model
1913 Bohr
Shell Model
1926 Quantum Mechanical
Model
Where are the electrons really?
1. (Shell) principle energy level (n) (1,2,3,4 …)
2. (Sub-shell) shape
(not rings)
s (1)
p (3) d (5)
3. (Orbital) 3-D arranged
x y
4. (Electron) spin up/down
HW p. 255
#57,60
z
f (7)
Electron Configuration
Orbital Notation
+8
Oxygen (O)
2
2
4
1s 2s 2p
energy
level
(shell, n)
Electron Configuration
Orbital Notation
+8
Oxygen (O)
2
2
4
1s 2s 2p
energy
level
(shell, n)
orbital
shape
(s,p,d,f)
Electron Configuration (arrangement)
Orbital Notation
+8
# of e–’s in each orbital
Oxygen (O)
2
2
4
1s 2s 2p
6
Na 1s2 2s2 2p6 3s1 How many valence e–’s?
(outer level)
Al 1s2 2s2 2p6 3s2 3p1
energy
orbital
level
shape
Cl [Ne] 3s2 3p5
(shell, n)
(s,p,d,f)
noble gas core
Aufbau: Fill lowest energy
orbitals first.
1s2 2s2 2p6 3s2 3p6 4s2 3d104p2
Hund: 1 e– in equal orbitals before pairing
()
(3d fills after 4s)
?
Pauli Exclusion:
no e–’s same props
(opp. spin) (↑↓)
nucleus
+
Electron Configuration of Ions
(i)
(ii)
(iii)
(iv)
(v)
Ion
F–
Ca2+
S2–
Na+
Al3+
E-Con
1s2 2s2 2p6
1s2 2s2 2p6 3s2 3p6
1s2 2s2 2p6 3s2 3p6
1s2 2s2 2p6
1s2 2s2 2p6
[Ne]
[Ar]
[Ar]
[Ne]
[Ne]
Which ions are isoelectronic?
F– , Na+ , Al3+
Ca2+ , S2–
List 3 species isoelectronic with Ca2+ & S2–.
P3– , Cl– , Ar, K+ , Sc3+ , Ti4+, V5+, Cr6+, Mn7+
Other Aspects
• Paramagnetic:
species are attracted by a magnet
(caused by unpaired electrons).
Fe:
[Ar] ↑↓
↑↓ ↑ ↑ ↑ ↑
4s
3d
• Diamagnetic:
species are slightly repelled by magnets
(caused by all paired electrons)
Zn:
[Ar] ↑↓
↑↓ ↑↓ ↑↓ ↑↓ ↑↓ (“di-” is 2)
4s
3d
HW p.255
Other Aspects
#74
• d block metals lose their outer s electrons
before any core d electrons to form ions.
Fe
1s2 2s2 2p6 3s2 3p6 4s2 3d6
Fe2+ 1s2 2s2 2p6 3s2 3p6 3d6
Fe3+ 1s2 2s2 2p6 3s2 3p6 3d5
• d block (trans. metals) have colored ions
due to light excited e– movement in d orbitals
Spectroscopy
EM REGION
SPECTROSCOPIC TECHNIQUE
TV/Radio (Rf) Nuclear magnetic resonance (NMR)
Infrared
IR (bond vibrations)
APPLICATION
Molecular Structure by
changes in nuclear spin.
Molecular Structure
by different bond vibrations
Visible/UV Vis/UV Atomic Emission Spectra Electron Transitions
(lines of frequencies/colors)
X-ray
between energy levels
PES (Photoelectron Spectroscopy) Electronic Config.
in atoms (by attraction & )
6 min Video Explanation of PES: https://www.youtube.com/watch?v=NR
IqXeY1R_I&feature=player_detailpage
Relative # of e–’s
Photoelectron Spectroscopy (PES)
Which peak is H and which is He?
higher peak = more e–’s
1s2
He 1s1
H
6
5
4
3
2
1
0
Binding Energy ...or Ionization Energy
(MJ/mol)
(required to remove e–’s)
 further left = more energy required
(stronger attraction
due to more protons)
Relative # of e–’s
Photoelectron Spectroscopy (PES)
Which peak is H and which is He?
6
2p
–
Ne
?
higher peak = more e ’s
1s2
Identify the
1
He
1s
2
1s2
2s
element
H
& e-config
6
5
4
3
2
1
0
Binding Energy ...or Ionization Energy
(MJ/mol)
(required to remove e–’s)
 further left = more energy required
(stronger attraction
due to more protons)
PES (A)
Identify
element
(A)
Ge
3d10
2p6
1s2
n=1
2s2
n=2
3p6
3s2
n=3
4s2 4p2
n=4
PES (B)
Identify
element
(B)
K
4s1
?
Write the complete electron configuration of
element (X), and identify the element.
1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p1
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p1
Ga
WS 3a
PES (X)
3d10
2p6
1s2
2s2
3p6
3s2
4s2 4p1
Chemistry, The Central Science, 10th edition
Theodore L. Brown; H. Eugene LeMay, Jr.; and Bruce E. Bursten
Unit 1 (Chp 7):
Periodicity
…or…
Periodic Trends in
Atomic Properties
John D. Bookstaver
St. Charles Community College
St. Peters, MO
 2006, Prentice Hall, Inc.
Periodic Trends
• We will explain observed trends in
size
Atomic (and Ionic) Radius
lose e– Ionization energy
attract e– Electronegativity
Zeff & shielding
(explains ALL periodic trends and properties)
Zeff & Shielding
• effective nuclear charge, (Zeff): Zeff = Z − S
Z = nuclear charge (+proton’s)
S = shielding (core e–’s)
attraction
• shielding, (S):
shielding
inner core e–’s shield valence
Zeff
e–’s from nuclear attraction.
Z = +11
+11
Na atom
Zeff = +1
Atomic Radius
decreases across a period
-due to increasing Zeff
(more protons)
att.
=shield
Zeff
increases down a group
-due to
increasing
shielding
(more
energy
levels)
att.
shield
=Zeff
Ionic Radius
e–
e–
Na+
•Cations are smaller than
neutral atoms.
outermost electron(s) are
removed and loses a shell
core shell closer to nucleus
inner e–’s shielded (Zeff)
Ionic Radius
e–
e–
e–
• Anions are larger than
their parent atoms.
electrons are added and
repulsions are increased
(=Zeff & =shielding)
Arrange the following species by
increasing size: Ar, K+, Ca2+, S2–, Cl–
Ca2+ < K+ < Ar < Cl– < S2–
Ionization Energy (IE)
•
•
•
•
energy required to remove an electron
more energy to remove each electron
IE1 < IE2 < IE3, … look for a huge jump in IE
once all valence e–’s are removed, the next e– is on
an inner level with attraction (shielding & Zeff).
huge jump in IE4 b/c 4th e– on inner level
(must have 3 valence e–’s)
Trends in First IE
increases across a period
WHY?
decreases down a group
Trends in First IE
IE tends to…
increases across a period
decreases down a group
-due to increasing Zeff
(more protons)
att.
=shield
Zeff
-due to
increasing
shielding
(more
energy
levels)
att.
shield
=Zeff
Does this graph support your
understanding of IE1 and the
Periodic Table?
5B
& 8O exceptions to trend. Why?
Exceptions to 1st IE Trend
1st IE tends to…increase across period
(Zeff , =shielding)
↑↓
↑
↑↓
B
Be
2s
2p
2s
1st IE of 5B < 4Be b/c…
The e– in 2p orbital of B is
higher energy than the e– in
2s orbital of Be ; less energy
needed to remove 1st e– in B.
OR
The 2p e– of B has more
shielding by the 2s e–’s.
Exceptions to 1st IE Trend
1st IE tends to…increase across period
(Zeff , =shielding)
O ↑↓ ↑↓ ↑ ↑
2s
2p
N ↑↓ ↑ ↑ ↑
2s
2p
1st IE of 8O < 7N b/c…
The paired e– in 2p orbital
of O experiences e–---e–
repulsion requiring less
energy to remove 1st e– in O.
Trends in Electronegativity (EN)
decreases down a group
-ability of an atom to attract electrons when bonded
(sharing e–’s) with another atom.
att.
increases across a period
=shield
-due to increasing Zeff
Zeff
(more protons)
-due to
increasing
shielding
att.
shield
=Zeff
Periodic Table
Elements arranged by…
atomic #
Periodic Table
Metals on the left
(80% of all elements)
Periodic Table
Nonmetals on the right
(except H)
Periodic Table
Metalloids border the stair-step
(Al is metal)
Periodic Table
• Rows on the periodic chart are called _______.
periods
• Columns are _______.
groups (# val.
e–’s)
(shell, n)
(energy level)
• Elements in the same ______
group have similar
_________________.
chemical properties
Group Names (1, 2, 17, 18)
1 2
17 18
Group 1: Alkali Metals
• soft, metallic • lowest IE’s (lose e–’s easily) Zeff
solids
• more reactive down a group
b/c…
video clip
shielding causes
att. & IE,
easier to lose e–
Group 2: Alkaline Earth Metals
• low IE’s, but not as low as alkali metals.
• less reactive than alkali metals (Zeff , att. & IE),
but more reactive down the group.
(shielding causes att. & IE)
Group 17: Halogens
•high IE’s (don’t lose e–’s easily) (Zeff , att.)
•large EN (attract e–) (Zeff , att.)
•more reactive at top of a group b/c…
shielding causes att. & EN,
easier for nonmetals to attract e–
Group 18: Noble Gases
• UNREACTIVE (mostly) b/c…
• HUGE IE’s b/c…… Zeff , att. (no lose e–), and
–)
filled
valence
shell
(no
gain
e
• Monatomic gases
Metals vs. Nonmetals
Table 7.3 p. 277 (in book)
Si
Metalloids:
• characteristics of metals & nonmetals.
• Silicon is shiny, but brittle and is a
semi-conductor.
Periodic Trends (Summary)
Electronegativity
Zeff & shielding
Atomic radius
Electronegativity
Can you explain all of this
in terms of p’s and e’s?
Periodicity:
–repeating pattern of properties
WS Periodicity
nonreactive
HW p. 292
soft highly
nonmetals
reactive metals
#13,28,38,46
highly reactive
WS 7a
nonmetals
harder less
reactive metals