Exam 4
Think of mass as
"frozen energy".
Beta nuclear symbol
0/-1B or 0/-1 e
Gamma nuclear symbol
0/0y
Amounts of background radiation - for most of us,
100 to 500 millirems per year.
Protons have a +1 charge, are in the nucleus of the atom, and weigh about
2000X that of an electron.
When at atom gives off an alpha particle the mass number decreases by
4
Alpha nuclear symbol
4/2 He
chain reaction
A self-sustaining reaction in which the products of one reaction event initiate further reaction events.
alpha particle
A subatomic particle consisting of the combination of two protons and two neutrons ejected by a radioactive nucleus. The composition of an alpha particle is the same as that of the nucleus of a helium atom
The atomic number decreases by 2 (so the new isotope effectively slips backwards across the periodic table and becomes a different, lighter element two paces back).
Alpha particle
There are three kinds of radioactivity
Alpha, Beta, Gamma
7. Plutonium (Pu) when it emits a beta particle
Americium, Am
atomic symbol
An abbreviation for an element or atom
Beta particle
An electron emitted during the radioactive decay of a radioactive nucleus.
E=mc2 (know what each letter represents)
An equation derived by the twentieth-century physicist Albert Einstein, in which E represents units of energy, m represents units of mass, and c 2 is the speed of light squared, or multiplied by itself.
Element
Any material that is made up of only one type of atom.
10. Carbn-14 when it emits a gamma particle
C
9. Carbon-12 when it emits a gamma particle
C
Radiation is measured in
Curies.
It is dangerous because it can cause DNA damage and destroys cells.
Gamma ray
gamma rays
High-frequency electromagnetic radiation emitted by radioactive nuclei.
Period (periodic table)
Horizontal rows on the periodic table
Tritium is an isotope of ___________.
Hydrogen
3. Hydrogen when it emits a gamma particle.
Hydrogen remains hydrogen
Uranium-235 is easy to use in a chain reaction but it is rare.
It is used for weapons.
Uranium-238 is the most common isotope of Uranium and is not very fissionable.
It is used in nuclear reactors to produce electricity.
1. Krypton (Kr) when emits an alpha particle
Kr become Se by losing two protons.
A Gamma particle can be stopped by a
Lead
5. Astatine (At) when it emits an alpha particle
Sulfur, S
Background radiation can come from
Sun, plants, water
transmutation
The changing of an atomic nucleus of one element into an atomic nucleus of another element through a decrease or increase in the number of protons.
Each shell can hold up to a certain number of electrons.
The innermost can hold up to 2, The second and third can hold up to 8 each.
16. What makes up an alpha particle?
Two protons and two neutrons (or one Helium nucleus)
Nuclear fusion does not involve
Uranium and Plutonium
6. Plutonium (Pu) when it emits an alpha particle
Uranium, U
Shell
a region of space around the atomic nucleus within which electrons may reside
groups on periodic table (also know as family)
a vertical row of elements in the periodic table
Three types of radioactive decay
alpha, beta, gamma
Nucleus
any subatomic particle found in the atomic nucleus; another name for either proton or a neutron
A "spent " fuel rod is not waste; much of it is U-238 and some is plutonium. Both of these
are highly fissionable and can be used to make weapons. Storage of spent rods is a concern that will have to be addressed.
That would all be a fission reaction. It is used in nuclear reactors and in smaller
atomic weapons.
one of neutrons in the nucleus has converted into a proton. So the atomic mass does not change, but the atomic number (number of protons) increases by one. The element slips forward across the periodic table and becomes a different, lightly heavier element.
beta particle
Different isotopes of the same element are identified by their mass number,
e.g. carbon-12 ( 6 protons and 6 neutrons) and carbon-14 ( 6 protons and 8 neutrons)
Atoms are made up of
electrons, neutrons, protons
So, a tiny bit of mass releases a phenomenal amount of
energy.
This missing mass is converted to
energy.
Parts of a nuclear reactor:
fuel rods, controls rods, primary loop (of water).
Nuclear fusion involves
fusing hydrogen nuclei into helium nuclei.
Energy can also be released when two nuclei are combined; that is a
fusion reaction. Currently a fusion reaction cannot be controlled; we find it inside stars (that's how they "burn") and in larger nuclear weapons.
We cannot yet control
fusion reactions
A fission reaction is when a heavy radioactive atom (like uraniuim or plutonium) is split into smaller atoms and some energy is
given off
A fusion reaction is when two small atoms (usually hydrogen) are fused together to make a heavier element, like
helium (or higher).
An alpha particle is basically 2 neutrons + 2 protons, no electrons. It looks just like a
helium nucleus.
Deuterium is a
hydrogen isotope consisting of one proton, one neutron and one electron
Energy and mass are
interchangeable.
The Sun converts about 5 million tons per second
into pure energy
The equation that relates mass to energy is e=mc2. Understand what it means, especially the "c2".
is the speed of light squared, or multiplied by itself.
Fusion reactions are currently found only in all stars (that is how they "burn") and
larger nuclear weapons.
A gamma ray,
like light, has no mass.
Fission reactions are used in small nuclear reactors to produce electricity or for
medicine
isotopes
members of a set of atoms of the same element whose nucleus contain the same number of protons but different number of neutrons.
The shell is not a physical thing; it is only a
model
1. Is there any matter at all in a gamma particle?
no
When an element gives off a beta particle, it moves forwards in the periodic table
one space.
Elements across a row in the periodic table tend to repeat their characteristics in other rows
periodically.
Basically a nuclear reactor produces steam in the secondary loop which is used to drive steam turbines to
produce electricity.
Elements within the same family on the periodic table have similar
properties
A Scintillation counter is another way of measuring
radiation, in addition to photographic film and Geiger counters.
Shells fill from the innermost one out; the outermost shell is the one exposed to the environment so those are the electrons that tend to
react.
Exposure to radiation is also measured in
rems and in rads.
When an element gives off a gamma particle it remains the
same element.
An alpha particle is pretty harmless and can be stopped by a
sheet of paper.
Within any one family of the periodic table the number of electrons in the outermost shell of each element is
similar
Fission reactions are found in small to medium
sized nuclear weapons.
Neutron have no charge, are in the middle of an atom, and weigh a teensy bit more than a proton. Probably made of a proton plus and electron plus
some sort of subatomic glue.
atomic mass
the mass of an element's atom listed in the periodic table as an average value based on the relative abundance of the element's isotopes
critical mass
the minimum mass of fissionable material needed for a sustainable chain recation
Alpha emission
the nucleus gives off an alpha particle - two neutrons and two protons combined together.
atomic number
the number of protons in the nucleus of an atom
Electrons have a -1 charge and are on
the outside of the atom. The number of protons is the same as the number of electrons in a neutral atom.
Radioactivity
the process of nuclear decay
half-life
the time required for half the atoms in a sample of a radioactive isotope to decay
mass number
the total number of protons and neutrons in the nucleus of an atom
A beta particle can be stopped by a
thin sheet of metal; they cause what looks like sunburns.
When an element gives off an alpha particle, it goes backwards in the periodic table
two spaces.
17. What makes up a beta particle?
One high-speed electrons, e-
2. Lead, Pb, when it emits a beta particle
Pb #82 becomes Bi #83.
Methods of measuring radiation:
Photographic film, Ionization counters (includes Geiger counters)
4. Radium (Ra) when it emits an alpha particle
Radon, Rn
8. Er when it emits a beta particle
Tm
