The periodic table is based on atomic number (the number of protons
and thus electrons), not on atomic mass. So the periodic table has
nothing to do with isotopes or why C12 might behave differently
When this discussion has started, I said that the key to
understanding is to understand the nature of isotopes. Since than,
each and every response I got, demonstrate that this particular piece
of totally eludes so many.
This is my last response. If you still do not get it, hit the books.
There is extensive literature on the subject. There is no need for me
to keep wasting my time, trying to remedy gaps in education.
Properties of any element are entirely defined by it's atomic
structure. Every element is born inside a star like our Sun. Inside
of stars composed from hydrogen in plasma state. From time to time, a
proton (hydrogen nucleus ) pushed towards outer surface of a star.
The further it is from the center, the lower the temperature and
proton can capture an electron and become hydrogen. Such atom
continues it's journey towards the surface and on it's way acquires
more protons and electrons and neutrons. With every acquisition it
becomes different element, with different properties.
The range of elements that star can produce is linked to it's
diameter. Our Sun upper range is iron. All the elements like copper,
gold, silver, and all other with atomic number greater than 56 are
alien to out solar system. They were produced by much larger stars.
The point to grasp here is that the only things that differ one
element from other is entirely depends on number of protons,
electrons, and neutrons. That is what Periodic law is about.
Isotope is an element, but with different amount of neutrons than
commonly occurs. Take a common element like hydrogen. One proton and
one electron. It's properties are well known. If atom of hydrogen
captures one neutron, it becomes one of the hydrogen isotopes -
deuterium. Water, where regular hydrogen is replaced with deuterium
is known as heavy water. By keep adding more neutrons we can create
different isotopes where elemental properties of hydrogen are
enhanced and another properties are added. Tritium contains 2
neutron and is no longer stable. It is radioactive. At present there
are 7 isotopes of hydrogen.
The same is observed with isotopes of other elements. The changes are
not as drastic like in hydrogen but they are there. In hydrogen
addition of one neutron to original nucleus increases nucleus mass by
almost one hundred percent, and corresponding changes are drastic as
well. We could tell the difference by observation. Going from carbon
12 to carbon 13, the change less than 4% in nucleus mass, so changes
are less pronounced but quantifiable. The thing to understand about
isotopes is that all original properties are preserved. The
difference is in increased density. Somewhat inaccurate comparison
could be made by analogizing with the difference between forged and
not forged iron. Forged iron has higher density and therefore better
mechanical properties. In a sense, we can call forged iron - a
mechanical isotope of regular iron. The meaning of isotope in this
analogy is stretched for demonstration purposes.