Write your abstract here. PART IV - Sulfur Came Before Oxygen Essential to Our Life - "Periodic Table of
Elements".
In addition to definitions
for the items placed in a table, and the description of the Pattern for the
data, there could certainly be an "Intended Use" of the table that
might become an important part of the table and affect the definition of data
terms and/or the definition of the pattern. Scientists working on the far
fringes of science
found atoms with various
numbers of protons, and noticed that other atoms with smaller number of protons
had not been
discovered. So, the use of this table was considered so accurate
that the guy discovering the substance with 25 protons could
"announce" that he had discovered a "missing element" like
a "missing cherry" but where there was clear evidence that it was missing
-- the element with 24 protons ! This was so useful that many otherwise unknown
elements were discovered simply because some scientist found an atom with a
number of protons NOT listed on the then-current Table of Elements.
This is a philosophical use
of the Table -- and the table is considered a profound "philosophical
statement" about chemistry -- as a "Philosophical" statement is
meant to mean true, but not based on direct observation -- more based on reason
and logic, within a philosophical framework. The "Pattern" then began
to get very fancy -- with the "Table" presented in both rows and
columns, like most "table" but where which row the element was in
made a big difference. In other words,
all the elements might be listed in ONE row, from Atomic Number One though
Atomic Number One Hundred (or whatever the current highest number was).
But if the first ten
elements were all gases (which they are not) and the next 20 elements were all
liquids (which is also not true) and all the rest were solid (not true,
either), then the table could be logically presented as having three rows, one
for gas, one for liquids and one for solids. The clever scientists son discovered that
there were elements that had very low atomic numbers -- the same range of
numbers as the gasses, but these were liquids, and that there even some solids
mixed in amongst the liquids if the only pattern were atomic number. Thus a
"new" Periodic Table would be announced from time to time, then the
pattern of THAT table was found to not fit all the observed data, so the
pattern would be modified or thrown out. Clever
chemists gained more and more confidence that this table could be successfully
used to predict
chemical properties such as what chemical would combine easily
with what other chemical. Sulfur and Oxygen ? Sulfur dioxide,
Oxygen and Hydrogen? H2O, Water
How
about Aluminum and Arsenic ? Well, I couldn''t find that as a chemical
compound. Perhaps I just missed it. If I understood the Periodic Table better I
could look at it and see whether aluminum and arsenic were capable of bonding
-- since "bonding" is one of the characteristics that can be gleaned
from the Table. There are two big ideas
in chemistry. They are chemical
periodicity and chemical bonding and they are deeply interconnected. The observation that certain elements prefer
to coine with specific kinds of elements prompted early chemists to classify
the elements in tables of chemical affinity. Later these table would lead, somewhat
indirectly, to the discovery of the periodic system, perhaps the biggest idea
in the whole of chemistry. Indeed,
periodic table arose partly through the attempts by Dimitri Mendeleev and
numerous others to make sense of the way in which particular elements enter
into chemical bonding. (Pg xiii, Scerri) "Triads" were
discovered even before the periodic table was in any full form. "Triads" simply meant a group of
three chemicals as shown in a list in the order of "atomic weights"
(similar to atomic number) that had similarities. German chemist
Dobereiner .. was the first to notice the existence of various groups of three
elements, subsequently called triads, which showed chemical similarities and
which displayed an important numerical relationship, namely, that the
equivalent weight, or atomic weight, of the middle element is the approximate
mean of the values of the two flanking elements in the triad. (Scerri, pg
42). Because of limited space, please read continuation in PART V - Sulfur Came Before Oxygen Essential to Our Life - "Periodic Table of Elements".