The Indianapolis times. [volume] (Indianapolis [Ind.]) 1922-1965, 1924-04-11
COMPOUNDS
FORMED B Y
ELEMENTS
Elections Wander About Sc
Chemical Mystery Is
Solved,
BY DAVID DIETZ,
Science Editor of The Times,
Copyright by David Dietz)

i-N | HE discovery Oh the way eleC-
irons were arranged to form
- atoms, solved one of the chief
mysteries confronting the chemist.
That was why certain elements
combined with others to form COM
pounds. For whilst there are thou
sands upon thousands of compounds
in existence, the chemist soon found
that there were certain definite rules
followed by the elements in forming
combinations.
Thus one atom of sodium unites
with one atom of chlorine to form a
molecule, of table salt. But two atoms
of hydrogen unite with one atom of
oxygen to form a molecule of water.
Two atoms of oxygen unite with one
atom of carbon to form a molecule
of carbon diOxide.
1t will be seen, therefore, that oxy-
gen has twice the combining power Of
sodium. while carbon, in the case of
carbon dioxide, has twice the combin
ing power of oxygen. or four times
the combining power Of sodium.
Element Has Value
The chemist calls the combining
power Of an element its valence and
speaks Of an element having a val
ence OF one, two, three or whatever
the case may be. Seven appears to
be the largest valence encountered.
Aside from the fact that elements
seem to show preferences for combin-
ing with certain other elements, it has
also been found that a few elements
do not form combinations at all. These
al re hr~f he oh
list and include the rare gases, helium,
argon, neon and krypton
The reason for the occurrence Of
chemical combinations is that the ar
rangement of the electrons around the
nucleus possesses varying degrees of
stability
1t will be remembered that the
electrons were arranged in zones
around the nucleus.
Helium has very stable atom, hav-
ing two electrons in the first zone.
and that zone VIII exactly hold two
electrons.
Lithium. however, has three cleo
irons, two In the first zone and one
in the second. Consequently there is
a tendency for the lithium atom TO
lose the lone electron in the second
zone.
Losing EIectrons
Some atoms seem to 9ttmept 10 OBJ
tain a stable confguration by losing
eiectrons so as TO empty an outer in
complete zone. other atoms seem to
obtain a stable confguration by gain
ing or appropriating enough electrons
n 90 cd .
zone.
Thus sodium has a tendency to
lose an electron. But chlorine has
tendency to gain an elecuon.
That Is why sodium and chlorine
unite 70 form table salt.
A molecule Of salt consists Of the
atoms arranged in such a way as TO
share one electron between them.
The chemist can not give very
clear picture Of just how the molecule
IS formed, but II seems that the two
nuclei are probably in motion or Vi
brating with respect TO each other.
All the eIectrons are revolving around
their respective nuclei with the ex
ception of the one electron which the
sodium atom has a tendency to lose.
This is probably revolving in some
complicated orbit about both nuclei.
Oxygen Gains Valence
An element like oxygen has ten
dency to gain or appropriate two
electrons. Hence 1t has valence
of two Certain atoms appear to be
able to gain electrons under some cir
cunnstances and to lose them under
others. Thus huorine under some
conditions has a tendency to lose
seven electrons under others, ten
dency to gain one
The inert elements have no ten
dency either to gain or lose, because
in each case their conhguration is
stable and complete.
It should be kept in mind that
in chemical combinations, changes
occur in the arrangement of the
cutter electrons. The nucleus under
goes no change.
Next article in series: Molecular
Structure.