Download metallic elements

METALLIC ELEMENTS
2/3 of elements
30 commonly used
Lhs of periodic table
Separated from Nonmetals by
the Semimetals B, Si, Ge, As,Te
Mostly mined as nonmetallic ores
(exception: some noble metals)
Criss
SEMINON-METALS
METALS
METALS
METALLIC ELEMENTS
2/3 of elements
30 commonly used
Lhs of periodic table
Alloys: mixtures of two or more metals
Steel = Fe + C (or Ni, V, Mo, Cr, Co, W...) tougher, less brittle than iron
Brass = Cu + Zn
Low T melting; easy to cast
Bronze = Cu + Sn
Ditto, also harder than Cu; corrosion resistant
Solder = Pb + Sn
Melts @ low T; joins other metals
METALLIC STRUCTURE
Metal atoms are positive ions in "sea of electrons"
Valence electrons in “cloud” or “conduction band”
Mutually shared;
Not attached to any particular nucleus
e.g,. native metals, Cu Au
COVALENT BOND
METALLIC BOND
IONIC BOND
METALS
NONMETALS
Metallic Bonding
Mostly Solids (except H, Hg)
Form positive ions
Generally high melting point
Liquid over hi T range (often >1000°C)
Covalent & Ionic Bonding
Mostly Gases
Form negative ions
Low M.P.
Liquid over low T range
(ELEMENTS)
=> can melt & cast
High electrical conductivity
High thermal conductivity (most)
Poor electrical conductors
Poor thermal conductors
except Si, Ge, C (Diamond = highest of all)
Special magnetic properties
Opaque
Metallic luster => ornament; coins
Malleable & Ductile
Weak to None
Transparent or Translucent
Dull
Brittle
cohesion; electron sea => machineable
Tough = withstand great strain
Brittle
w/o breaking, tearing =>many uses
High tensile strength
Low tensile strength
exception: Carbon Nanotubes =strongest fiber
Reactive to inert
Alkali metals
Noble metal: Cu Ag Au = coins
Form many compounds
NASA
Oct 22, 2004
SOLAR ABUNDANCES
Solar Photosphere is similar to chondritic meteorites (except for H, He…)
Similar to bulk Earth
Earth is residue of preexisting stars
1)  Large amounts of H (>93 atom %) and He (>6 at.%)
Primordial composition; stellar fuel
2)  Heavier elements all very rare (∑ ~ 0.1 atom %); essentially trace elements !
3) Progressive, exponential-like decline with atomic number Z
4) Abundance minimum at Li, Be, B
5)  Abundance peaks at C, O, Fe.
High for nuclides with Mass # A of multiples of 4 = a particle mass
Bulk Earth > 92 wt % Fe, O, Si, Mg {56Fe, 16O, 28Si, 24Mg}
6) Tc (Z=43) and Pm (Z=61) missing- all nuclides radioactive w short half lives
4.2 Ma for 98Tc; but Tc is known in stellar spectra Z => active nucleosynthesis
7)  No stable nuclides for Z > 83 (Bi)
8)  Even/Odd effect: Harkin's rule.
Elements w/ even atomic #’s are more abundant than those w/ odd at. #’s
Also true for isotopes of a single element
=> Nuclear Effect, not a Chemical Effect
Confirms compositional measurements by F.W. Clarke (Chief Chemist)
& H.S. Washington (USGS 1889 -1930's).
Log Abundance
12
H
He
10
CO
8
Solar Photosphere
data in Lodders & Fegley 1998
Mg Si
Fe
6
4
2
Th
0
Tc
0
20
40
U
Pm
60
Atomic Number, Z
80
100
0.7
CI Meteorites
Concentration, ppm
Ce
0.6
data from Loders & Fegley 1998
0.5
Nd
0.4
0.3
Dy
Gd
La
0.2
0.1
0
Pr
Pm
56
Er
Sm
58
60
Eu
62
Tb
64
Ho
66
Atomic Number, Z
Tm
68
Yb
Lu
70
72
30
Sn Isotopes
data from Walker et al 1989
25
20
15
105
110
115
120
125
Mass Number A
2.1h
9.6d
105a
0
129d
5
115d
55a
10
18m
4.1h
35m
Abundance, Atom %
35
130
ABUNDANT METALS
Al
OTHER 1.4%
5.4%
Mg
14.9%
SILICON
OXYGEN
14.6%
31.7%
IRON
32.0%
Bulk Earth
Estimate of
Kargel & Lewis 1993
ABUNDANT METALS > 0.1 wt. % of Earth's crust
ELEMENT
BULK EARTH
Table 4.2 Henderson
Mg
Al
Si
Ti
Mn
Fe
Oxygen
12.7
1.1
15.2
0.05
0.2
34.6
CRUSTAL
ABUNDANCE
2.3%
8.2
28.2
0.57
0.095
5.6
29.53
~45
> 93 %
90 %
EARTH: Differentiated planet
Crust
Mantle (Mg,Fe)SiO4
Core, NiFe
uppermost 10-100 km
1215 - 3490 km
3490 -6370 km
http://www.ufrgs.br/cebi/terra/estrutura_en.html
Log Abundance
12
H
He
10
CO
8
Solar Photosphere
data in Lodders & Fegley 1998
Mg Si
Fe
6
4
2
Th
0
Tc
0
20
40
U
Pm
60
Atomic Number, Z
80
100
USGS
REE Uses: fiber optics, color cathode ray tubes, catalysts,
small hi-strength magnets, magnetic refrigeration, fluorescent tubes,
computer disk drives, defense applications
USGS