The
Elements| The
Elements |
In General > s.a. atomic physics.
@ General references: Ball 04.
@ Periodic system: Scerri AS(97) [and electrons],
SA(98)sep [evolution];
Kak Sandhan(04)phy [history,
Mendeleev]; Kibler qp/06/FC
[application of SO(4,2) 
SU(2)];
Scerri AS(08)jan [history and developments in classification system].
> Online resources:
American Elements website [properties
and uses of elements].
0: Positronium, Ps
* Idea: An e+e– bound
state; Orthopositronium (spins pointing in the same direction)
has a lifetime of about 150 ns.
* Use: Measuring the
annihilation decay rates provides unique tests of QED.
@ References: Vallery et al PRL(03)
+ pw(03)may
[lifetime];
Fleischer et al PRL(06)
+ pn(06)jan
[Ps–].
1: Hydrogen, H > s.a. quantum
systems.
* Idea: The simplest,
and the most abundant element in the universe, by far.
* Properties: Auto-ignites
at 500 ºC.
* Metallic form: 1935,
Existence proposed by Wigner; Initial attempts made with crystalline
structure;
1996, Obtained in disordered state, at pressures > 1.4
Mbar [@ LLNL 1996
page; Weir et al PRL(96)
+ pn(96)mar].
@ General references: PW(95)jul issue; Rigden
02.
@ Related topics: Blanford et al PRL(98)
+ pn(98)apr
[anti-H]; Korsheninnikov
et al PRL(01)
+ pn(01)aug
[5H], PRL(03)
[7H, considered inconclusive]; news pw(05)aug
[hydrino state]; news pn(07)jul
[7H].
2: Helium, He > s.a. quantum
systems.
* Idea: The second most
abundant element in the universe, but it was only seen in the Sun's spectrum
in 1868, and discovered on Earth (in a uranium mineral) in 1895!
* Isotopes: 8He
has been observed, and seems to have a "halo" of
4 neutrons surrounding a 4He core; 2001, 9He
with an extra neutron in
a second outer shell was formed for 10–20 seconds
by shooting 11Be
nuclei into a target of 9Be atoms.
@ References: Hallock PT(98)jun
[3He
in 2D]; Chen et al PLB(01)
[9He isotope]; news pw(06)oct
[universal abundance puzzle]; news pn(08)may
[2He observed!].
3: Lithium, Li
4: Beryllium, Be
5: Boron, B
@ References: Eremets et al Sci(01)
+ pw(01)jul
[superconductivity at high pressure].
6: Carbon, C > s.a. molecular
physics.
* Forms: Carbon occurs
naturally as the soft, black graphite and as
diamond; The only difference between the two is the
arrangement of the atoms; The same carbon atoms can also be arranged
into a "chicken wire" pattern and rolled up into miniscule "nanotubes" only
10 atoms across, with rather extraordinary properties.
* Diamond: Created at
high p and T inside Uranus, conditions
recreated in the lab [@ news pn(99)oct].
* Radiocarbon dating:
Began in 1949 with Willard Libby's suggestion that the amount of 14C
left in a fossil object could provide an estimate
of how old
the
object was; The thinking
was that the organism, while it was alive, would constantly ingest enough
of the rare 14C to replace those
nuclei that were decaying into 14N (the
other products being an electron and a neutrino); But as soon as the organism
died, the ratio of 14C/12C
would begin to drop exponentially since the 14C
was no longer being replaced. Measuring the ratio in terms of radioactive
half-lives
would provide a good estimate of the fossil.
* Nanotubes: Discovered
in 1991 by Iijima, they consist of sheets of graphene rolled-up into cylinders
of 1–10 nm diameter, so they are quasi-1D; Extremely stiff, with
a Young's modulus of 1.0–1.8 TPa (100 times the tensile strength
of steel), they buckle elastically; They can be better conductors than
copper or semi-conductors, depending on
how they
are rolled
up, and are excellent heat conductors; > s.a. technology.
@ Radiocarbon dating: Beck et al Sci(01)jun;
Holt et al PRL(08) + pn(08)jan [explanation of long 14C half-life].
@ Nanotubes: Dresselhaus et al pw(98)jan;
Dekker PT(99)may; Chen et al Sci(99)jul;
issue pw(00)jun.
@ Other topics: Agranat et al JETPL(97)
+ pn(98)feb
[liquid]; news pw(06)nov
[graphene and spintronics].
7: Nitrogen, N
* New forms: 2001, Non-molecular polymer-like opaque solid with semiconducting
properties, formed around 140 GPa, hysteresis effect makes it stable at atmospheric p, can store energy.
@ References: Eremets et al Nat(01)may
+ pw(01)may
[new form]; Pilyugin et al A&A(03)ap/02,
Chiappini et al ap/05/A&A
[origin].
8: Oxygen, O
@ References: Shimizu et al Nat(98)jun
[superconducting]; Gorelli et al PRL(99)
[O4 molecules at high p]; Freiman
& Jodl PRP(04)
[solid O].
9: Fluorine, F
10: Neon, Ne
11: Sodium, Na
12: Magnesium, Mg
13: Aluminum, Al
14: Silicon, Si
* History: 2001, Japanese
scientists formed Si cage clusters, analogous to C fullerenes [@ Hiura et al PRL(01)
+ pn(01)feb].
* Use: A vital material for the semiconductor industry and one of
the most studied elements in all of science.
15: Phosphorus, P
16: Sulfur, S
17: Chlorine, Cl
18: Argon, Ar
19: Potassium, K
20: Calcium, Ca
21: Scandium, Sc
22: Titanium, Ti
23: Vanadium, V
24: Chromium, Cr
25: Manganese, Mn
26: Iron, Fe
27: Cobalt, Co
28: Nickel, Ni
29: Copper, Cu
30: Zinc, Zn
31: Gallium, Ga
32: Germanium, Ge
33: Arsenic, As
* Properties: Metalloid.
34: Selenium, Se
* Properties: Nonmetal.
35: Bromine, Br
* Properties: Halogen liquid.
36: Krypton, Kr
* Properties: Noble gas.
37: Rubidium, Rb
* Properties: Alkaline metal.
38: Strontium, Sr
* Properties: Alkaline earth metal.
39: Yttrium, Y
* History: Its discoverer, Johann Gadolin, named it after the Swedish
town of Ytterby.
* Properties: Transition metal; in pure form, silvery-colored, but
found in most rare-earth mineral combinations.
* Use: Make red phosphors for TV and computer monitors.
40: Zirconium, Zr
* Properties: Transition metal.
41: Niobium, Nb
* Comments: Named after Niobe, daughter
of Tantalus; Used in searches for fractional charges.
42: Molybdenum, Mo
* Comments: From the greek "molybdos",
lead; Occurs only in impure forms in nature.
43: Technetium, Tc
* History: The first element to be synthetically produced, in 1937.
* Where: The only one of the first 92 elements not found naturally
on Earth (except possibly in minute traces).
* Properties: Radioactive, but 99Tc
has 
1/2 = 210,000 yr.
* Use: Used in nuclear medicine for examination of liver and blood,
and to identify some stars.
44: Ruthenium, Ru
45: Rhodium, Rh
46: Palladium, Pd
47: Silver, Ag
* Properties: Transition metal.
48: Cadmium, Cd
* Properties: Transition metal.
49: Indium, In
* Properties: Metal.
50: Tin, Sn
51: Antimony, Sb
52: Tellurium, Te
53: Iodine, I
54: Xenon, Xe
* Where: A noble gas, present in our atmosphere with concentrations
below one part per million.
* Use: For commercial production, xenon is extracted by liquefying
air at low temperature and high pressure, and then separating the xenon from
other
components. Its main use is in various types of lights, including some
automobile
headlamps, stroboscopes, and as an exciter in some laser applications.
56: Barium, Ba
57: Lanthanum, La
58: Cerium, Ce
59: Praseodymium, Pr
60: Neodymium, Nd
61: Pm
62: Samarium, Sm
63: Europium, Eu
64: Gadolinium, Gd
65: Terbium, Tb
66: Dysprosium, Dy
67: Holmium, Ho
68: Erbium, Er
69: Thulium, Tm
70: Ytterbium, Yb > s.a. Bose-Einstein
Condensation.
* Properties: Has longest-lived
known excited state, 3700 days [@ Roberts
et al PRL(97)].
71: Lutetium, Lu
72: Hafnium, Hf
73: Tantalum, Ta
* Properties: Ta-180 is the rarest naturally occurring isotope.
74: Tungsten, W
75: Rhenium, Re
76: Osmium, Os
77: Irisium, Ir
78: Platinum, Pt
79: Gold, Au
80: Mercury, Hg
81: Thallium, Tl
82: Lead, Pb
83: Bismuth, Bi
84: Polonium, Po
* Properties: The only
element with a simple cubic crystal structure (the result of the complicated
set of orbital energy states of the electrons and their spin-orbit couplings,
made more complicated by the interplay of relativistic effects–specifically
the relativistic increase in electron mass at high velocities);
Because of its crystal structure, its elastic anisotropy is greater than for
any other solid; Has 36 isotopes, more
than
any
other
element, and is highly radioactive; Polonium is a hazardous element that appears
in the air and soil and in such plants as tobacco, tea, and mushrooms.
@ References: news pn(07)jun.
85:
86:
87: Francium, Fr
* Properties: Least stable
of first 103 elements, less than 1 oz exists on Earth at any time, but not
hard to produce.
@ Trapped: news pn(96)may;
PT(96)jun;
Simsarian et al PRL(96).
88:
89:
90: Thorium, Th
91:
92: Uranium, U
93:
94: Plutonium, Pu
* Properties: One of
the most unusual metals – it's not magnetic and it does not conduct electricity
well; The material also changes its size dramatically with even the slightest
changes in its temperature and pressure; Used as fuel for nuclear weapons and
power plants.
@ References: news pn(07)mar
[theory of properties].
95:
96:
97:
98: Californium
99:
100: Fermium, Fm
102: Nobelium, No
104: Rutherfordium, Rf
105: Hahnium
106: Seaborgium, Sg
@ References: Schädel et al Nat(97)jul
[chemical properties].
107: Bohrium
* Properties: Extremely unstable, and not found in nature. Experiments
on chemical properties done with longer-lived (about 20 sec) isotope at LBL.
110: Darmstadtium, Ds
* History: 1994, Discovered
at the GSI lab in Darmstadt, and quickly seen in other experiments at Berkeley
and the JINR laboratory in Russia – However, none of the observations
confirmed the
others because they all produced different isotopes of the new element; 2003,
Confirmed [@ Ginter et al PRC(03)
+ pw(03)jul].
111: ?
* History: 2003, Discovered
at the GSI lab in Darmstadt [news pw(03)oct].
112:
?
* Properties: =
280 ms.
@ References: Armbruster & Hessberger SA(98)sep [2 atoms of 112
made].
113: "Ununtrium"
* History: Announced in 2004 by Dubna group as decay product from #115;
Atoms lived up to 1.2 s.
@
References: Oganessian et al PRC(04)
+ pw(04)feb.
114: ?
* History: 1999, Russian-Livermore discovery, unconfirmed.
* Properties: =
30 s; Island of stability?
@ References: Oganessian et al SA(00)jan [island of stability].
115: "Ununpentium"
* History: Production
of 4 atoms announced in 2004 by Dubna group; Lived for about 90 ms.
@ References: Oganessian et al PRC(04)
+ pw(04)feb.
116: ?
* History: 1999, Discovered
at Lawrence Berkeley National Lab, by crashing krypton atoms into Pb atoms
[@ news pn(99)jun,
pn(06)oct].
118: ?
* History: 1999, Discovery
announced at Lawrence Berkeley National Lab, like #116 [@ news pn(99)jun];
2001–2002,
Discovery retracted after an internal review committee found that data purporting
to show the existence of the new element had
been fabricated [@ news pn(01)aug];
2006, Discovery announced again by JINR-Lawrence Livermore National Lab collaboration
[@ news pn(06)oct, pw(06)oct].
119: ?
120: ?
@ References: Smolanczuk PLB(01).
Main page – Abbreviations – Journals – Comments – Other
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Send feedback and suggestions to bombelli at olemiss.edu – Modified
28 jun 2008