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The Periodic Table
1
The Periodic Table
Development of the periodic table (8.1)
y Periodic classification of the elements
(8.2)
y Periodic variation in physical properties
(8.3)
y Ionization energy (8.4)
y Electron affinity (8.5)
y Variation in chemical properties of the
representative elements (8.6)
y
8.1 and 8.2 Development of the periodic
table and periodic classification
In what year was the modern periodic
table developed?
y How was the periodic table put together?
y
ns2np6
ns2np5
ns2np4
ns2np3
ns2np2
ns2np1
d10
d5
d1
ns2
ns1
Ground State Electron Configurations of the Elements
4f
5f
Figure 8.1, p. 255
8.1 and 8.2 Development of the periodic
table and periodic classification
In what year was the modern periodic
table developed?
y How was the periodic table put together?
y
In what year were electrons discovered?
y In what year were protons discovered?
y
When the Elements Were Discovered
8.1 and 8.2 Development of the periodic
table and periodic classification
8.1 and 8.2 Development of the periodic
table and periodic classification
Figure 8.2, p. 257
8.1 and 8.2 Development of the periodic
table and periodic classification
What are core electrons?
y How do these vary by period?
y
He (2 core e-)
Ne (10 core e-)
Ar (18 core e-)
Kr (36 core e-)
Xe (54 core e-)
8.1 and 8.2 Development of the periodic
table and periodic classification
What are valence electrons?
y How do these vary by group?
y
1 2
3 4 5 6 7 8
8.1 and 8.2 Development of the periodic
table and periodic classification
y
How are electron configurations of ions
determined and written?
Electron Configurations of Cations and
Anions of Representative Elements
8.1 and 8.2 Development of the periodic
table and periodic classification
Na [Ne]3s1
Na+ [Ne]
Ca [Ar]4s2
Ca2+ [Ar]
Al [Ne]3s23p1
Al3+ [Ne]
Atoms gain
electrons so
that anion has
a noble-gas
outer electron
configuration.
Atoms lose
electrons so that
cation has a noblegas outer electron
configuration.
H 1s1
H- 1s2 or [He]
F 1s22s22p5
F- 1s22s22p6 or [Ne]
O 1s22s22p4
O2- 1s22s22p6 or [Ne]
N 1s22s22p3
N3- 1s22s22p6 or [Ne]
-1
-2
-3
+3
+2
+1
Cations and Anions Of Representative Elements
Figure 8.1, p. 255
Electron Configurations of Cations
of Transition Metals
8.1 and 8.2 Development of the periodic
table and periodic classification
When a cation is formed from an atom of a transition
metal, electrons are always removed first from the ns
orbital and then from the (n – 1)d orbitals.
Fe:
[Ar]4s23d6
Fe2+: [Ar]4s03d6 or [Ar]3d6
Fe3+: [Ar]4s03d5 or [Ar]3d5
Mn:
[Ar]4s23d5
Mn2+: [Ar]4s03d5 or [Ar]3d5
8.1 and 8.2 Development of the periodic
table and periodic classification
How are electron configurations of ions
determined and written?
y What is isoelectronic?
y Which species are isoelectronic?
y
Na
K+
Ne
Cl–
O2–
K
Ca2+
Al3+
Cl
Sc2+
Na+
Ti4+
S2–
Ar
Kr
8.3 Atomic and Ionic size
Do all electrons feel the same nuclear
charge?
y What is shielding?
y What is effective nuclear charge?
y
Effective Nuclear Charge
8.3 Atomic and Ionic size
Na
Mg
Al
Si
P
S
Cl
Z
11
12
13
14
15
16
17
Core
Zeff
10
1
10
2
10
3
10
4
10
5
10
6
10
7
σ
Zeff
8.8
2.2
9.15
2.85
9.5
3.5
9.85
4.15
10.2
4.8
10.55
5.45
10.9
6.1
Effective Nuclear Charge
8.3 Atomic and Ionic size
Li
Na
K
Rb
Cs
Fr
Z
3
11
19
37
55
87
Core
Zeff
2
1
10
1
18
1
36
1
54
1
86
1
σ
Zeff
1.7
1.3
8.8
2.2
16.8
2.2
33.3
3.7
51.3
3.7
81.2
5.8
Effective Nuclear Charge (Zeff) increases across a period from left to right
Effective Nuclear Charge (Zeff) increases
down a group from top to bottom
Effective Nuclear Charge
8.3 Atomic and Ionic size
Margin Figure, p. 259
8.3 Atomic and Ionic size
Do all electrons feel the same nuclear
charge?
y What is shielding?
y What is effective nuclear charge?
y How does this affect the size of atoms?
y
◦ How do we determine the size of atoms?
8.3 Atomic and Ionic size
Radius = ½ the distance between the centers of the atoms
Figure 8.3, p. 260
8.3 Atomic and Ionic size
Atomic size increases down a group
from top to bottom
Atomic Size
Atomic size decreases across a period from left to right
Figure 8.2, p. 257
8.3 Atomic and Ionic size
Do all electrons feel the same nuclear
charge?
y What is shielding?
y What is effective nuclear charge?
y How does this affect the size of atoms?
y
◦ How do we determine the size of atoms?
y
How does atomic size change when ions
form?
8.3 Atomic and Ionic size
Cation is always smaller than atom from
which it is formed.
Anion is always larger than atom from
which it is formed.
Figure 8.7, p. 262
Ionic Size
8.3 Atomic and Ionic size
Figure 8.6, p. 262
Ionic Size
8.3 Atomic and Ionic size
Figure 8.8, p. 263
8.4 Ionization energy
What is ionization energy?
y What is the periodic trend for ionization
energy?
y
8.4 Ionization energy
Ionization Energy decreases down a
group from top to bottom
Ionization Energy increases across a period from left to right
Margin Figure, p. 265
8.4 Ionization energy
Figure 8.9, p. 266
8.4 Ionization energy
What is ionization energy?
y What is the periodic trend for ionization
energy?
y What is the difference between 1st and
successive ionization energies?
y
8.4 Ionization energy
Table 8.2,
p. 265
8.5 Electron Affinity
What is electron affinity?
y How can this be represented in a
thermochemical equation?
y
Table 8.3, p. 268
8.6 Descriptive Chemistry
Read p. 268-278
y You will be tested on only those concepts
that you have already been tested and/or
taught. For example:
y
◦ The electron configuration of calcium
◦ The reaction of sodium with water
◦ The metallic character periodic trends
(consider group 4)
Chapter 8 – Practice