PGCC CHM 101 Sinex Periodic Table of the Elements The Chemists Organizational Chart.
To discuss element origin, lets divide the elements into · -made in the center of stars. 2....
Transcript of To discuss element origin, lets divide the elements into · -made in the center of stars. 2....
To discuss element
origin, lets divide
the elements into
two categories.
1. Naturally Occurring
-made in the center
of stars.
2. Synthetic
-made in the lab
by people
Chemists have identified
93
such elements, three
of which are not
found on Earth.
Tc, Pm, Np are found in the
spectra of stars.
According to
the Big BangTheory,
the universe began with
the explosion of
a single primeval atom.
!
Temperatures were in
the millions of Kelvins.
Matter does not exist at
such temperatures. All
was energy. (E=mc2)
It is believed that the
universe cooled as it
expanded.
Some of the energy was
converted to matter.
(p+, n, e-)
Continued cooling
allowed these subatomic
particles to come
together forming
HYDROGEN.
H
Hydrogen atoms grouped
together and fused in
the heat, forming
helium.
He-4
These reactions
provide E which
serves as fuel for
the sun. This is
how high temps.
are maintained.
HOT!
The higher temp. allows
He to fuse, creating
heavier elements like
C, N, O, Fe and Ni.
When a star uses
up the H and He
it collapses,
becoming a...
Atoms are torn apart
during formation of the
red giant.
p+ n
These stray particles are
taken up by other nuclei,
forming elements heavier
than Fe and Ni.
The star will eventually
explode as a...
spreading
matter across
millions of
kilometers.
This is how we believe
the Earth was “seeded”
with elements.
Natural elements were
formed by nuclear
reactions that occurred
in the sun.
…a change in the
composition of the
nucleus of an atom
Synthetics-White Letters
Synthetic elements are
made from a
transmutation.
…the process of changing
one nucleus into another
by radioactive disintegration
or bombardment with
other particles.
Early in the century,
scientists were studying
the tracks made by alpha
particles through
water vapor in
cloud chambers
Harkins
& Blackett
Photos…
Page 146
Figure 4-33
Alpha +
Nitrogen
collision
H
O
4
2 He + 14
7 N
17
8 O + 1
1 H
Oxygen formation
Transmutation reactions
soon began to be studied
in cyclotrons, or particle
accelerators.
2 “D”
Shaped
Magnets
With a
Gap.
In a cyclotron, ions are
accelerated and collide with
a target nuclei to create an
element with a much higher
atomic number.
Problem: Heavier elements
accelerate more slowly.
A synchroton can get particles
to hit head-on creating more
energy. This allows creation
of the “superheavies.”
--cheaper than
a cyclotron
Particles are given “a push” now
and then as they go around this
facility.
Have an atomic number
greater than 106.
Many of these elements
only last for a few
thousands of a second.
. …because we can
…to learn about
nuclear structure
Some elements are given
a 3 letter abbrev. until
a name is decided.
Do you recognize any
of the names?