How many elements as per the periodic table are synthetic?


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iceng5 years ago
The synthetically prepared elements are
(with name, symbol, atomic number):

technetium (Tc), 43
promethium (Pm), 61
neptunium (Np), 93
plutonium (Pu), 94
americium (Am), 95
curium (Cm), 96
berkelium (Bk), 97
californium (Cf), 98
einsteinium (Es), 99
fermium (Fm), 100
mendelevium (Md), 101
nobelium (No), 102
lawrencium (Lr), 103
rutherfordium (Rf), 104
dubnium (Db), 105
seaborgium (Sg), 106
bohrium (Bh), 107
hassium (Hs), 108
meitnerium (Mt), 109
darmstadtium (Ds), 110
roentgenium (Rg), 111
copernicium (Cn), 112


6 other elements have been confirmed to exist, but the names and symbols given are provisional as no names for the elements have been agreed upon by IUPAC.


ununtrium (Uut) 113
ununquadium (Uuq) 114
ununpentium (Uup) 115
ununhexium (Uuh) 116
ununseptium (Uus) 117
ununoctium (Uuo) 118

 
lemonie iceng5 years ago
I used to do IUPAC naming for organic chemicals, fun but in a logic-problem sort of way...

L
iceng lemonie5 years ago
Bill Lear searched long and hard for a suitable replacement for H2O as
the working fluid in the steam bus.  Named Learium but ultimately came
to be known as unobtainium.  
Some fluids were poisonous and an explosive decompression would
coat every internal high pressure surface with Teflon.  The antidote for
inhaling the Learium de jour vapors was alcohol ergo all employees
were supplied a half gallon of JB Scotch to be kept in their desk drawer.

It wasn't often but on a tiring Friday afternoon it wasn't unusual to have
a steam engineer smell a vapor leak and we would all take some of
the antidote (several shots to be sure ).

A
If you are wondering which kinds of atoms are found in nature, and which kind are "created" in the laboratory, or in industry (e.g. inside a nuclear reactor), via the arcane art of nuclear science, then to answer this question the word "element" is not specific enough.

This is the case because which element an atom is, is determined by one number, Z, the number of protons that atom has.  But the number of neutrons, N,  is important too.  If you are interested in both Z and N, then what you want is a table of isotopes rather than a table of elements. I'll link to an example of this table later (hint: It's much bigger than the classic periodic table of elements.)  But first let me explain why the distinction between "element" and "isotope" is important.

For example, regarding synthetic or natural, you might ask:  Is iodine(53 protons) a naturally occurring element, or is it synthetic?   The answer is yes or no, depending on which isotope you're talking about.  Iodine atoms with 53 protons and 74 neutrons (called Iodine-127) are stable and found in nature, in abundance in the Earth's oceans.  In contrast Iodine-131 (with 53 protons and 78 neutrons) is definitely synthetic, not natural.  I-131 is what they call a "fission product".  It's made in fission reactors, and it's intensely radioactive, with a half-life of only about 8 days.  That particular isotope came to mind because of that nuclear meltdown thing a few months back in Fukushima, Japan.  There was a lot of talk in the news about I-131, and other isotopes and FUD.  Then the malfs at Fukushima never really got fixed, and the news-reporters decided that was too scary to talk about anymore, so they stopped talking about it.

Back to this question of which atoms are "synthetic" and which are "naturally occurring".  It really just comes down to a question of stable versus unstable, which is really just a question of half-life.    That is to say isotopes with a half life shorter than about 100-million years, are not found in significant amounts in the Earth's crust.  Why?  Simply because the Earth is much older than that.  In fact radioactive decay is one of those big clues as to the grand question of, "How old is the Earth anyway?"

By the way, if you want to know a little more about isotopes: which are stable, which are unstable, what fractions tend to occur in nature... there is a little blurb on the right-hand column of every Wikipedia article about an element, and the title of that blurb is "Most stable isotopes" E.g. in the article for Iodine,
http://en.wikipedia.org/wiki/Iodine
Wiki lists four, of which only one is truly stable and "naturally occurring".  But like I was saying before, "stable" and "naturally occurring" are logically equivalent.  One implies the other.

So generally speaking which atoms are stable, and which are not  is the same question as which atoms are "naturally occurring" and which are "synthetic"?  And this all leads to that big table of isotopes, or chart of nuclides, I mentioned earlier.  It's a plot with Z (number of protons) on one axis, and N (number of neutrons) on the other.  Then you give each isotope a color corresponding to its half-life, i.e a color indicating how stable/unstable it is, and the result is this big blob that kind of looks like an island.

I think it's worth your time to ponder the larger versions of this table which can be found on the web, e.g. here:
http://en.wikipedia.org/wiki/Table_of_nuclides
and a really nice interactive version here:
http://www.nndc.bnl.gov/chart/

This funny island shaped looking thing is a pretty good summary of everything nuclear science knows about how atoms are put together.

In response to your original question, the little black squares on this chart represent atoms which are stable enough to be  "naturally occurring", and all the other colored squares are "synthetic", sufficiently unstable that the only way to obtain them is through some sort of nuclear process, e.g. via nuclear reactor, particle accelerator, etc.


table_of_isotopes.png
ankur2893 (author)  Jack A Lopez5 years ago
Do u have this picture in a better resolution by any chance?
ankur2893 (author)  Jack A Lopez5 years ago
oh, sorry mate, didn't read the last line, it really is fascinating!
Fascinating :-o
nurdee15 years ago
To the best of my knowledge all elements over Uranium are synthetic or man made.
FoolishSage5 years ago
Have you tried wikipedia? 118 known elements, 94 of which are natural and 24 artificial. I suppose the artificial elements might be natural in some far flung corner of the universe though..