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history of an atom
mean - physical science
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Stellar Nucleosynthesis
The formation of
elements
in the center of a
star
The formation of the universe began through the explosion of a
primordial atom
which happened approximately
13.7
billion years ago
Big Bang theory
Theory introduced by
Edwin Hubble
describing the origin of the
universe
In
1929
, Hubble demonstrated that all
celestial
objects in the universe move away from each other
Big Bang Nucleosynthesis
1.
Protons
and neutrons combined to form light elements Hydrogen and
Helium
2. Other light elements such as
Lithium
and
Beryllium
were also formed during this process
Nebula
Giant cloud of
gas
and
dust
Formation of a protostar
Gravity
pulls
Hydrogen
gas together until it spins faster and faster and becomes ignited
Formation of a main sequence star
1.
Nuclear fusion
occurs at the core, it begins to contract, glow and become stable
2.
Hydrogen
is converted into
Helium
Formation of a red giant
1.
Star
is unable to generate
heat
when it runs out of hydrogen in its core, leading to its contraction and expansion
2.
Helium
fused into
Carbon
3.
Star
cools down and glows
red
Formation of a white dwarf
1. Red giant star becomes exhausted of
nuclear
fuel, the
outer
material is blown off into space leaving the inert Carbon
2. The remnant is known as a
white
dwarf
Formation
of a
black dwarf
The
hypothetical remnant
of a
white dwarf
that has cooled down and no longer emits light and heat
Formation of a red supergiant
1. More massive
main sequence star
evolves,
cools
and expands faster than low mass star
2.
Carbon fusion
still occurs and
Oxygen
formed
Supernova
Explosion of star releases large amount of
energy
,
dispersing
elements into space
Neutron star
Formed from
supernova explosion
, the
smallest
star
Black hole
Region in space where
gravity
is too strong that no matter can
escape
from it
Proton-proton chain reaction
1. Proton and
neutron
fuse to form
deuterium
2.
Deuterium
fuses with another proton to form
Helium-3
3.
Two Helium-3
atoms fuse to form
Helium-4
CNO cycle
Carbon,
Nitrogen
, Oxygen cycle used by massive stars to convert Hydrogen into
Helium
Tri alpha
process
Three
Helium-4
atoms are converted into Carbon in
red giant stars
Alpha ladder process
Fusion of alpha particles in the core of a
red supergiant
creates heavier elements up to
Iron
Neutron capture
A
neutron
is added to a seed nucleus to form a
heavier
nucleus
process (
slow
process)
Slow rate of neutron capture, faster rate of
radioactive decay
increases the
proton number
by 1
process (
rapid
process)
Faster
rate of neutron capture before radioactive decay, more neutrons can be combined in the nucleus, occurs in
supernovae
Supernova is the source of elements heavier than
Iron
, which are
dispersed
into space
Evidence of star formation includes energy emitted during
nuclear
reactions, including ultraviolet,
infrared
, X-ray, radio wave and microwave
Atomic
number
The number of
protons
(
positively
charged particles) in an atom
In 1913, Henry
Moseley
demonstrated that the
atomic number
determines most of the properties of an element
In
1919
, Ernest Rutherford successfully carried out a nuclear transmutation reaction, transforming one element or
isotope
into another
In
1925
, there were
four
unknown elements in the periodic table that corresponded to atomic numbers 43, 61, 85, and 87
Particle accelerator
Device used to speed up
protons
to overcome the repulsion between
protons
and target atomic nuclei, used to synthesize new elements
Transuranium
elements
Elements with atomic numbers greater than
92
(atomic number of uranium), discovered in the
laboratory
Mendeleev's
periodic table
Classification of elements based on their
atomic weight
, demonstrating a
periodic pattern
of physical and chemical properties
Hydrogen
is the
lightest
element on the periodic table, with an atomic mass of 1.00794 amu
Hydrogen
is the most
abundant
element on the periodic table
x-r
a
y spectrosco
py
Method of identifying elements by shooting electrons at them and measuring the X-rays they emit
Moseley's
experiments showed that the frequency of
X-rays
emitted by an element is proportional to its atomic number
The gaps in
Mendeleev's
periodic table corresponding to atomic numbers 43, 61, 85, and 87 were later filled by
synthesized
elements
Nuclear
transmutation
Transformation of one
element
or
isotope
into another element
The first
nuclide
prepared by artificial means was an isotope of
oxygen
, 17O, made by Rutherford in 1919</b>
Neutrons are used instead of positively charged particles to synthesize new elements, as they do not
repel
the target
atomic nuclei
Technetium
(Tc) was the first man-made element, synthesized by bombarding molybdenum with
deuterons
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