Madame Curie

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Lecture 53

• Madame Curie

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Henri Becquerelturned the study of they
radioactive uranium to Marie Curie
Marie Curies husband joined Marie and together
they discovered a new more powerful minerals
called polonium and radium.
it took four more years of processing tons of ore
under oppressive conditions to isolate enough of
each element to determine its chemical
properties.
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Their laboratory was nothing more than a
miserable hangar, where in winter the temperature
dropped to around six degrees. One chemist
commented that "it looked more like a stable or a
potato cellar".
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And yet, Marie admitted that "one of our
pleasures was to enter our workshop at night
then, all around us, we would see the luminous
silhouettes of the beakers and capsules that
contained our products".
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In 1903, Marie defended her thesis and together
with Becquerel, the Curies were awarded the Nobel
Prize for Physics for their discovery of natural
radioactivity.
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She did not quit

• She also had to fight the prejudices of her day
• hatred of foreigners and sexism which, in 1911,
  prevented her from entering the Academy of
  Science

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After the war she spent the rest of her life
obtaining and working with radium in order to
treated cancer patients
Marie died of leukemia in July, 1934, exhausted
and almost blinded, her fingers burnt and
stigmatized by "her" dear radium.
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Nuclear the science of the change of the nucleus
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Bacquerel put the mysterious mineral on top of
the plate and it effected the film even though
the film case was not opened

• Bacquerel was too busy with his study of
  fluorescence so he gave the research of the
  mysterious minerals to his assistant Mrs Curie

Mrs Curie called the phenonemena radioactivity
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Through studies it was learned that this
radioactivity was caused by the nucleus of an
atom that shoots out alpha particles, beta
particles and gamma rays
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We know the nucleus made up of

• Electrons mass of 0 negative charge
• Protons mass of 1 positive charge
• Neutrons mass of 1 neutral charge

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As we have said in the past

• The number of protons dictates what something is
• 7 protons
• 9 protons

The number of neutrons may make it heavier or the
number of electrons will give it a particular
charge but the number of protons dictates what it
is
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If we could add protons, one by one,
experimentally to an atom we would proceed to
form one element to the next.

• The mass of the elements do not however increase
  in mass quite so nicely.
• The strange and sometimes unpredictable
  increases in mass of elements are due to the
  number of neutrons that are present in the
  nucleus.

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To designate the weight of an element when
writing the complete name of an element you write
the atomic symbol

• atomic number as a subscript and the mass number
  as the superscript

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• How many neutrons
• How many protons
• If it is neutral
• How many electrons

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• How many neutrons
• How many protons
• How many electrons

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Not all atoms of the same element have the same
mass.

• all forms of Lithium have 3 protons, however
  some lithium have 3 neutrons and some have 4
  neutrons.

If there is more than one mass number for a
particular element the elements are considered
isotopes.
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You name a element specifically by stating the
element and then the mass

• Carbon 13 has a mass of 13
• Neon 23 has a mass of 23
• polonium 218
• Plutonium 240
• radium 226

How many protons how many neutrons
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While there are 110 or so elements there are 1500
isotopes of those 110 elements

• Carbon has two isotopes.
• Carbon 12 6 protons and 6 neutrons
• carbon 13 6 protons and 7
  neutrons
• Nitrogen has two isotopes
• Nitrogen 14 7 protons and 7
  neutrons
• Nitrogen 15 7 protons and 8
  neutrons

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The general name for the nucleus of an atom is
called the Nuclide

• Nucleus means center
• Nuclide means center of atom

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Most of the isotopes are stable meaning they do
not have a tendency to alter themselves to be in
a more stable state.

• Other isotopes are unstable. These unstable
  isotopes to need to change to become stable. In
  order to be more stable the isotope will lose or
  in some way eject part of the nuclide and in
  doing so decrease the number of protons or
  neutrons. By decreasing the number of protons
  the element itself changes.

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When the number of protons change and the atomic
number changes then the element changes and this
is called a transmutation. Nuclei that
undergo transmutation are said to be radioactive
or undergoing radioactive decay.
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For a unstable nucleus to become stable the
element must obtain the correct proton to neutron
balance. If that balance does not exist the
nucleus will eject a particle until the stability
is obtained.
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It is kind of like when you eat too much and need
to barf you hurl until you feel better

• An unstable atom will barf until it is stable
  but what cookies, what chunks does it hurl????

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Atoms spew typically one of four things

• 1) alpha radiation the nucleus of a helium
  atom it has a 2 charge has a weight of 4 and
  contains 2 protons 2 neutrons
• 2) beta radiation
• a) e or an electron has a 1 charge, no mass
  and contains 1 electron.
• b) positron a positive electron with a charge
  of 1 no mass
•  3) gamma radiation, no mass no charge is like
  light and high power radio waves
• 4) Neutron loss or neutron capture no charge
  change but mass will alter by a unit of one
•  

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Dont mix up electron stability and the loss and
or gain of electrons where cations or anions are
created and nuclear radiation .. These are two
different issues
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One more thing about alpha beta and gamma
radiation. There is ionizing and no ionizing

• Ionizing radiation is radiation that puts a
  charge on what it hits. Most ionizing radiation
  is high power gamma radiation.

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Radioactive Decay 

• Nuclear decay is a exothermic reaction, it is the
  process where a atom goes from a unstable state
  into a more stable state
• And it becomes stable by spewing out radioactive
  puke

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In nuclear decay the initial nucleus is called
the parent nucleus. And the new nucleus is
called the daughter nucleus.  
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One kind of nuclear decay is when an alpha
particle is ejected. Remember that an alpha
particle is 2 protons and 2 electrons with a 2
charge and is written 
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What would happen to an atom that underwent alpha
particle decay

• It would lose how many protons?
• It would lose how many neutrons?
• It would lose how much in overall mass?

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To show radioactive decay of thorium by alpha
particle decay in an equation type format you show
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•  
• 1)     Write an equation to represent the decay
  of radium 226 by alpha emission
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• 2)     Write an equation to represent the decay
  of plutonium 240 by alpha emission

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• 3) The decay products from a nuclear reaction are
  an alpha particle and polonium 218. What is the
  parent nuclide in this reaction?

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So a alpha particle will stabilize a nucleus
that has too many protons.
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What if instead of losing an alpha particle a
beta particle is radiated out of the nucleus?????
A beta particle is an electron A particle that
has a mass of 0 and a charge of -1
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So where does the beta particle (electron) come
from. Are they stuck in-between the neutrons
and protons of the nucleus like lone socks stuck
between shirts in the laundry only to fall out
when you least expect them
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No..

• Like some kind of perverted worm the electron is
  spewed from the inside of a neutron
• does the neutron lose any mass when it spits the
  electron out???????

The neutron stays the same mass but because the
neutron kicks out a negative charge it is no
longer neutral.
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The neutron mutates into a proton

• If the neutron becomes a proton then the element
  changes into a new element

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How would you write the chemical equation for the
beta emission of Neon 23
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What if instead of losing an alpha particle a
beta particle is radiated out of the nucleus?????

• If a beta particle radiates does the nucleus lose
  any mass????

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Sometimes an electron falls inside
Electron capture where an electron goes inside a
nucleus and changes a proton into a
neutron Neutron capture where a neutron is
absorbed
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Gamma and the tent example
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? 10n ? 14256Ba 9136Kr 3 10n
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We now see that some atoms have nucleuses that
not only have enough neutrons to neutralize the
protons, they have soooo many that the nucleolus
is actually unstable
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These unstable nucleases will spew out parts of
the oversized nucleus to obtain the proper
neutron to proton ratio and become more stable .

• This occurs via the gain or loss of alpha
  particle beta particle neutron or gamma ray