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Authored by: Wol on Saturday, April 06 2013 @ 07:24 AM EDT |
Heat energy ... there's actually no such thing. Heat is EITHER microwave
(infra-red) radiation, ie photons, OR it's kinetic energy - the *random*
movement of particles.
Either way, the transfer of heat is easy to understand - either two particles
collide, transferring kinetic energy, or one atom chucks out a photon which is
then absorbed by another atom.
As for flow of electrons - well - that's the bit of CHEMISTRY that interests me
most! I'd say Physical Chemistry is my special interest. You'll notice that the
metals are all clustered to the left and bottom of the periodic table, with all
the insulators to the top and right - and the "noble gases" on the far
right.
With the noble gases, every SUB-shell is full, therefore all the electrons are
tightly held, therefore they are insulators and pretty chemically inert. With
the metals on the left, you have a lone electron or two with a whole shell to
itself to wander as it wishes. It's very easy for these electrons to jump from
orbit to orbit, so when you apply a potential difference across a wire, they
flow easily.
That's why potassium, for example, will explode when you drop it into water. The
electrons are so eager to jump into an H shell, giving off heat as they do so,
that it melts the potassium (speeding up the reaction even more), releases
hydrogen gas, and ignites the gas in the air!
It's also why the elements on the right of the periodic table tend to form
stable compunds. Because their shells are nearly full, when they acquire extra
electrons they hang on to them tight. The other thing to bear in mind is that
electrons can orbit two nuclei - that's what makes a chemical bond. So, to take
water for example, hydrogen has one electron and needs two to fill its first
shell. Oxygen has 2+6 electrons, but needs 8 to fill the second shell. So
hydrogen atom the first shares its electron in return for sharing an oxygen
electron and hydrogen atom the second does the same. So we now have four
electrons solely in the oxygen outer shell, two shared with the first hydrogen,
and two with the second. So each hydrogen "thinks" it has a full
complement of 2, and the oxygen "thinks" it has a full complement of
2+8.
The other thing to remember is pairs of electrons are always more stable than
lone electrons, so any element with an odd atomic number is always likely to be
more reactive than the even numbered ones either side.
Cheers,
Wol[ Reply to This | Parent | # ]
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