Transcript Where Did the Elements Come From?

Where Did the Elements
Come From?
Section 4.4
Natural and Synthetic Elements
• Not all elements are found on
Earth – some were found in
the spectra of the stars
• Synthetic elements have been
created by man
Stars
• Big bang THEORY
• Explosions
• Temperature only E could exist
• Cooling  matter produced
Nuclear Reactions
• Rxn involving a change in the
composition of the nucleus of an
atom
• Centers of stars, H nuclei fused
to form He
• Nuclear fision takes place at
extremely high temps
Stars
• As H is used up, the star shrinks and
becomes hot
• This causes He to fuse and form
elements with higher atomic
numbers
• Fe and Ni are the largest formed by
this (believed to be in Earth’s core)
The Sun
• When this happens in a sun sized
star, it collapses and expands as a
red giant
• When this forms, other parts of
nuclei are produced and larger
elements than Fe and Ni are
produced
Artificial Elements
• Transmutation – the process of
changing one nucleus into
another by radioactive
disintegration or bombardment
w/ other particles
Transmutations
• Transmutation rxns were
discovered by bombarding
elements with alpha particles
• Cyclotron – device that shoots
charged particles with E pulses
at elements
Synchrotron
• Used to create superheavy
elements
• Particles in cyclotron can only
reach max speed until it arrives
for the next pulse too late.
Synchrotron
• Matches the acceleration of the
particles
• Accelerates fewer types of
particles but reaches higher E
than a cyclotron
Superheavy Elements
• When particles interact head on,
they allow massive nuclei to
interact and create superheavy
elements.
• SHE = element with atomic #
higher than 106
Superheavy Elements
• Some of these elements last only
for a few seconds.
• When meitnerium was created, it
lasted for only 0.0034 seconds.