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Periodic Table of the Elements
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
2
Periodic Table of Elements 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
11
Hydrogen 1.00794
H1 Atomic #
Name Atomic Weight
SymbolC Solid
Hg Liquid
H Gas
Rf Unknown
Metals NonmetalsAlkali metals
Alkalineearth m
etals
Lanthanoids
Transition m
etals
Poor metals
Other
nonmetals
Noble gasesActinoids
2
Helium 4.002602
He2 K
23
Lithium 6.941
Li21 4
Beryllium 9.012182
Be22 5
Boron 10.811
B23 6
Carbon 12.0107
C24 7
Nitrogen 14.0067
N25 8
Oxygen 15.9994
O26 9
Fluorine 18.9984032
F27 10
Neon 20.1797
Ne28
KL
311
Sodium 22.98976928
Na281
12
Magnesium 24.3050
Mg282
13
Aluminium 26.9815386
Al283
14
Silicon28.0855
Si284
15
Phosphorus 30.973762
P285
16
Sulfur 32.065
S286
17
Chlorine 35.453
Cl287
18
Argon 39.948
Ar288
KLM
419
Potassium 39.0983
K2881
20
Calcium 40.078
Ca2882
21
Scandium 44.955912
Sc2892
22
Titanium 47.867
Ti28
102
23
Vanadium 50.9415
V28
112
24
Chromium 51.9961
Cr28
131
25
Manganese 54.938045
Mn28
132
26
Iron 55.845
Fe28
142
27
Cobalt 58.933195
Co28
152
28
Nickel58.6934
Ni28
162
29
Copper 63.546
Cu28
181
30
Zinc 65.38
Zn28
182
31
Gallium 69.723
Ga28
183
32
Germanium 72.63
Ge28
184
33
Arsenic 74.92160
As28
185
34
Selenium 78.96
Se28
186
35
Bromine 79.904
Br28
187
36
Krypton 83.798
Kr28
188
KLMN
537
Rubidium 85.4678
Rb28
1881
38
Strontium 87.62
Sr28
1882
39
Yttrium 88.90585
Y28
1892
40
Zirconium 91.224
Zr28
1810
2
41
Niobium 92.90638
Nb28
1812
1
42
Molybdenum95.96
Mo28
1813
1
43
Technetium (97.9072)
Tc28
1814
1
44
Ruthenium 101.07
Ru28
1815
1
45
Rhodium 102.90550
Rh28
1816
1
46
Palladium 106.42
Pd28
1818
0
47
Silver 107.8682
Ag28
1818
1
48
Cadmium 112.411
Cd28
1818
2
49
Indium 114.818
In28
1818
3
50
Tin 118.710
Sn28
1818
4
51
Antimony 121.760
Sb28
1818
5
52
Tellurium 127.60
Te28
1818
6
53
Iodine 126.90447
I28
1818
7
54
Xenon 131.293
Xe28
1818
8
KLMNO
655
Caesium 132.9054519
Cs28
1818
81
56
Barium 137.327
Ba28
1818
82
57–7172
Hafnium 178.49
Hf28
183210
2
73
Tantalum 180.94788
Ta28
183211
2
74
Tungsten 183.84
W28
183212
2
75
Rhenium 186.207
Re28
183213
2
76
Osmium 190.23
Os28
183214
2
77
Iridium 192.217
Ir28
183215
2
78
Platinum 195.084
Pt28
183217
1
79
Gold 196.966569
Au28
183218
1
80
Mercury 200.59
Hg28
183218
2
81
Thallium 204.3833
Tl28
183218
3
82
Lead 207.2
Pb28
183218
4
83
Bismuth 208.98040
Bi28
183218
5
84
Polonium (208.9824)
Po28
183218
6
85
Astatine (209.9871)
At28
183218
7
86
Radon (222.0176)
Rn28
183218
8
KLMNOP
787
Francium (223)
Fr28
183218
81
88
Radium (226)
Ra28
183218
82
89–103104
Rutherfordium (261)
Rf28
18323210
2
105
Dubnium (262)
Db28
18323211
2
106
Seaborgium (266)
Sg28
18323212
2
107
Bohrium (264)
Bh28
18323213
2
108
Hassium (277)
Hs28
18323214
2
109
Meitnerium (268)
Mt28
18323215
2
110
Darmstadtium (271)
Ds28
18323217
1
111
Roentgenium (272)
Rg28
18323218
1
112
Copernicium(285)
Cn28
18323218
2
113
Ununtrium (284)
Uut28
18323218
3
114
Flerovium(289)
Fl28
18323218
4
115
Ununpentium (288)
Uup28
18323218
5
116
Livermorium(292)
Lv28
18323218
6
117
Ununseptium Uus
118
Ununoctium (294)
Uuo28
18323218
8
KLMNOPQ
For elements with no stable isotopes, the mass number of the isotope with the longest half-life is in parentheses.
Periodic Table Design and Interface Copyright © 1997 Michael Dayah. http://www.ptable.com/ Last updated: May 9, 2013
57
Lanthanum 138.90547
La28
1818
92
58
Cerium 140.116
Ce28
1819
92
59
140.90765
Pr28
1821
82
60
Neodymium 144.242
Nd28
1822
82
61
Promethium (145)
Pm28
1823
82
62
Samarium 150.36
Sm28
1824
82
63
Europium 151.964
Eu28
1825
82
64
Gadolinium 157.25
Gd28
1825
92
65
Terbium 158.92535
Tb28
1827
82
66
Dysprosium 162.500
Dy28
1828
82
67
Holmium 164.93032
Ho28
1829
82
68
Erbium 167.259
Er28
1830
82
69
Thulium 168.93421
Tm28
1831
82
70
Ytterbium 173.054
Yb28
1832
82
71
Lutetium 174.9668
Lu28
1832
92
89
Actinium (227)
Ac28
183218
92
90
Thorium 232.03806
Th28
18321810
2
91
Protactinium 231.03588
Pa28
183220
92
92
Uranium 238.02891
U28
183221
92
93
Neptunium (237)
Np28
183222
92
94
Plutonium (244)
Pu28
183224
82
95
Americium (243)
Am28
183225
82
96
Curium (247)
Cm28
183225
92
97
Berkelium (247)
Bk28
183227
82
98
Californium (251)
Cf28
183228
82
99
Einsteinium (252)
Es28
183229
82
100
Fermium (257)
Fm28
183230
82
101
Mendelevium (258)
Md28
183231
82
102
Nobelium (259)
No28
183232
82
103
Lawrencium (262)
Lr28
183232
92
Michael Dayah For a fully interactive experience, visit www.ptable.com. [email protected]
Praseodymium
Electronegativity¡ Electronegativity, symbol χ, is a chemical property
that describes the tendency of an atom to attract electrons (or electron density) towards itself.
¡ The electronegativity difference Δχ between two atoms determine how likely one atom will rob the other of electrons, and this in turn determines what kind of bonds are formed between two atoms.¡ Large Δχè Ionic bonds¡ Small Δχè Covalent bonds
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
3
Measures of Electronegativity¡ Pauling electronegativity¡ Most commonly used definition based on valence bond theory¡ Difference in A-B bond strength vs A-A and B-B bond strength
¡ Arbitrary reference is H, set at 2.20.
¡ Mulliken electronegativity¡ Arithmetic mean of the first
ionization energy and the electron affinity
¡ Also known as absolute electronegativity
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
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Ionic bonding¡Bonding involving electrostatic attraction
between oppositely charge ions.
¡Non-directional, and geometry tends to follow maximum packing rules. Often leads to much higher coordination numbers.
¡Large Δχ
¡Example: LiF¡ Pauling χLi = 1.0, χF = 3.98¡ Li “donates” an electron to F to form Li+ and F-
¡ Both Li+ and F- have highly stable full octet
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
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Covalent bonding¡ Bonding that involves sharing of electron pairs
between atoms, typically to achieve stable full outer shell
¡ Highly directional, with geometry determined by Valence shell electron pair repulsion VSEPR rules
¡ Favored by small Δχ
¡ Example: H2 molecule¡ The two H shares two electrons, forming a full He shell for each
H.
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
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Other types of bonds¡Metallic bonds¡ Metals readily give up their weakly bound outer
electron(s) to become positive ions in a “sea” of electrons.
¡ Valence electrons are not closely associated with any particular atom, resulting in free motion and high electrical conductivity.
¡Van Der Waals bonds¡ Due to small instantaneous charge redistributions, which
cause an effective polarization of the molecule, i.e. centers of gravity of positive and negative charges do not coincide.
¡ Polarization result in effective attractive force.
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
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Pauling’s rules¡Five rules published by Linus Pauling in 1929
for determining the crystal structures of complex ionic crystals.
¡Before we discuss these rules, it is important to first establish the concept of atomic and ionic radii.
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
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Atomic and ionic radii¡Size of an atom / ion depends on size of nucleus
and number of valence electrons
¡Atoms with larger number of electrons generally have a larger size than atoms with smaller number of electrons
¡Size of ions ≠ Size of atoms as ions have gained or lost electrons¡ As charge on ion increases, there will be less electrons
and the ion will have a smaller radius.¡ As the atomic number increases in any given column of
the Periodic Table, the number of protons and electrons increases and thus the size of the atom or ion increases.
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
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Determination of Ionic Radii¡X-ray crystallography (final third of course)
can provide distances between ions.
¡However, this does not tell us where the boundary between ions are, and hence does not provide information on ionic radii.
¡One trick is therefore to choose ions that are extremely different in size, e.g. Li+ and I-. In LiI, the Li+ are effectively in the interstitial sites with the I- touching each other, allowing one to determine the radii of I-
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
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Pauling’s First Rule¡ A coordinated polyhedron of anions is formed about
each cation, the cation-anion distance determined by the sum of ionic radii and the coordination number by the radius ratio.
¡ Derived purely from geometric considerations of sphere packing
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
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Applying Pythagoras’ theorem, we get Rx/Rz= 0.732
Coordination and radius ratios
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
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Radius ratio C.N. polyhedron
0.225 4 tetrahedron
0.414 6 octahedron
0.592 7 capped octahedron
0.645 8 square antiprism (anticube)
0.732 8 cube
0.732 9 triaugmented triangular prism
1 12 cuboctahedron
Pauling’s Second Rule: The electrostatic valence rule
¡ An ionic structure will be stable to the extent that the sum of the strengths of the electrostatic bonds that reach an anion equal the charge on that anion, i.e., a stable ionic structure must be arranged to preserve local electroneutrality.
¡ Electrostatic valency is defined as charge on ion / coordination number
where εis the charge of the anion and the summation is over the adjacent cations.
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
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ε = sii∑
Pauling’s Third Rule¡ The sharing of edges and particularly faces by two anion
polyhedra decreases the stability of an ionic structure. Sharing of corners does not decrease stability as much, so (for example) octahedra may share corners with one another.
¡ Effect is largest for cations with high charge and low C.N. (especially when r+/r- approaches the lower limit of the polyhedral stability).¡ Vertex-sharing between tetrahedra or octahedra is energetically
stable¡ Edge-sharing between polyhedra is less stable; rare for
tetrahedra, more common for octahedra¡ Face-sharing (2 cations share 3 anions) between polyhedra is
unstable; never occurs for tetrahedra; rare for octahedra
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
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Pauling’s Fourth Rule¡ In a crystal containing different cations, those
of high valency and small coordination number tend not to share polyhedron elements with one another.
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
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Pauling’s Fifth Rule: The rule of parsimony
¡ The number of essentially different kinds of constituents in a crystal tends to be small. The repeating units will tend to be identical because each atom in the structure is most stable in a specific environment. There may be two or three types of polyhedra, such as tetrahedra or octahedra, but there will not be many different types.
NANO 106 - Crystallography of Materials by Shyue Ping Ong - Lecture 7
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