Title: Madame Curie
1Lecture 53
2Henri 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.
3Their 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".
4And 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".
5In 1903, Marie defended her thesis and together
with Becquerel, the Curies were awarded the Nobel
Prize for Physics for their discovery of natural
radioactivity.
6She 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
7After 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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10Nuclear the science of the change of the nucleus
11Bacquerel 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
12Through 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
13We know the nucleus made up of
- Electrons mass of 0 negative charge
- Protons mass of 1 positive charge
- Neutrons mass of 1 neutral charge
14As 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
15If 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.
16To 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
17- How many neutrons
- How many protons
- If it is neutral
- How many electrons
18- How many neutrons
- How many protons
- How many electrons
19 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.
20You 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
21While 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
22The general name for the nucleus of an atom is
called the Nuclide
- Nucleus means center
- Nuclide means center of atom
23Most 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.
24When 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.
25For 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.
26It 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????
27Atoms 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 - Â 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 - Â
28Dont 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
29One 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.
30Radioactive DecayÂ
- 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
31In nuclear decay the initial nucleus is called
the parent nucleus. And the new nucleus is
called the daughter nucleus. Â
32One 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 writtenÂ
33What 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?
34To show radioactive decay of thorium by alpha
particle decay in an equation type format you show
35- Â
- 1)Â Â Â Â Write an equation to represent the decay
of radium 226 by alpha emission - Â
36- 2)Â Â Â Â Write an equation to represent the decay
of plutonium 240 by alpha emission
37- 3) The decay products from a nuclear reaction are
an alpha particle and polonium 218. What is the
parent nuclide in this reaction?
38So a alpha particle will stabilize a nucleus
that has too many protons.
39What 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
40So 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
41No..
- 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.
42The neutron mutates into a proton
- If the neutron becomes a proton then the element
changes into a new element
43How would you write the chemical equation for the
beta emission of Neon 23
44What 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????
45Sometimes 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
46(No Transcript)
47Gamma and the tent example
48? 10n ? 14256Ba 9136Kr 3 10n
49We 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
50These 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