(Los Angeles) Investigators say two survivors may have provoked a tiger at the San Francisco Zoo by throwing rocks and metal discs at the animal before it escaped and killed one person. Sandra Mitchell reports.
(New York) Falling debris falls into a car in Chelsea. Metal debris falls off a high line train trestle into the windshield of a car. The passenger was rushed to the hospital with injuries.
Aluminium
From Wikipedia, the free encyclopedia
This article may require cleanup to meet Wikipedia's quality standards.
Please improve this article if you can. (December 2007)
"Aluminum" redirects here. For other uses, see Aluminum (disambiguation).
13
magnesium ? aluminium ? silicon
B
?
Al
?
Ga
Periodic table - Extended periodic table
General
Name, symbol, number
aluminium, Al, 13
Chemical series
poor metals
Group, period, block
13, 3, p
Appearance
silvery
Standard atomic weight
26.9815386(13)?g·mol-1
Electron configuration
[Ne] 3s2 3p1
Electrons per shell
2, 8, 3
Physical properties
Phase
solid
Density (near r.t.)
2.70 g·cm-3
Liquid density at m.p.
2.375 g·cm-3
Melting point
933.47 K
(660.32 °C, 1220.58 °F)
Boiling point
2792 K
(2519 °C, 4566 °F)
Triple point
543253 K (542980°C), kPa
Heat of fusion
10.71 kJ·mol-1
Heat of vaporization
294.0 kJ·mol-1
Heat capacity
(25 °C) 24.200 J·mol-1·K-1
Vapor pressure
P/Pa
1
10
100
1 k
10 k
100 k
at T/K
1482
1632
1817
2054
2364
2790
Atomic properties
Crystal structure
face centered cubic
0.40494 nm
Oxidation states
3, 2 [1], 1 [2]
(amphoteric oxide)
Electronegativity
1.61 (Pauling scale)
Ionization energies
(more)
1st: 577.5 kJ·mol-1
2nd: 1816.7 kJ·mol-1
3rd: 2744.8 kJ·mol-1
Atomic radius
125 pm
Atomic radius (calc.)
118 pm
Covalent radius
118 pm
Miscellaneous
Magnetic ordering
paramagnetic
Electrical resistivity
(20 °C) 26.50 nO·m
Thermal conductivity
(300 K) 237 W·m-1·K-1
Thermal expansion
(25 °C) 23.1 µm·m-1·K-1
Speed of sound (thin rod)
(r.t.) (rolled) 5000 m·s-1
Young's modulus
70 GPa
Shear modulus
26 GPa
Bulk modulus
76 GPa
Poisson ratio
0.35
Mohs hardness
2.75
Vickers hardness
167 MPa
Brinell hardness
245 MPa
CAS registry number
7429-90-5
Selected isotopes
Main article: Isotopes of aluminium
iso
NA
half-life
DM
DE (MeV)
DP
26Al
syn
7.17?105y
?+
1.17
26Mg
e
-
26Mg
?
1.8086
-
27Al
100%
Al is stable with 14 neutrons
References
This box: view ? talk ? edit
Aluminium (IPA: /??lj?'m?ni?m/, /??lj?'m?ni?m/) or aluminum (/?'lu?m?n?m/, see spelling below) is a silvery white and ductile member of the poor metal group of chemical elements. It has the symbol Al; its atomic number is 13. Aluminium is the most abundant metal in the Earth's crust, and the third most abundant element overall, after oxygen and silicon. It makes up about 8% by weight of the Earth?s solid surface. Aluminium is too reactive chemically to occur in nature as the free metal. Instead, it is found combined in over 270 different minerals.[1] The chief source of aluminium is bauxite ore. Aluminium is remarkable for its ability to resist corrosion (due to the phenomenon of passivation) and its light weight. Structural components made from aluminium and its alloys are vital to the aerospace industry and very important in other areas of transportation and building.
