Nuclear Physics Flashcards
Describe the structure of an atom.
a positively charged nucleus and negatively charged electrons in orbit around the nucleus
How can atoms form positive ions?
losing electrons
How can atoms form negative ions?
gaining electrons
What is an experiment to support the nuclear model of the atom?
scattering of alpha particles by a sheet of thin metal
What does Rutherford’s Alpha Particle Scattering experiment prove?
- there is a very small nucleus surrounded by mostly empty space
- nucleus contains most of atom’s mass
- positive nucleus
What is the nucleus composed of?
protons and neutrons
Relative charge of proton?
+1
Relative charge of neutron?
0
Relative charge of electron?
-1
What is the proton number?
number of protons found in the nucleus
The electron and proton numbers are equal in…
an atom (neutral)
The electron and proton numbers are unequal in…
ions (charged)
What is the nucleon number?
total number of protons and neutrons in the nucleus
What is the mass number?
total number of protons and neutrons in the nucleus
How can you calculate the number of neutrons in a nucleus?
nucleon number - proton number
What is the symbol A?
nucleon number
What is the symbol Z?
proton number
What is the symbol X?
element
What is the symbol for an element?
X
What is the symbol for nucleon number?
A
What is the symbol for proton number?
Z
What is an isotope?
atoms of the same element with the same number of protons and electrons, but different neutron numbers
What is an isotope, in terms of nucleon and proton numbers?
different nucleon number of the atoms, same proton number
Describe the process of nuclear fusion.
lighter nuclei collide with high energy and join to form a larger nucleus, releasing energy
What is the difference between nuclear fission and fusion?
nuclear fission - splitting of heavy nuclei
nuclear fusion - joining of 2 light nuclei
What is the nuclide equation for nuclear fusion?
- you add the nucleon and proton numbers
- total nucleon number is the same before and after
Describe the process of nuclear fission.
- heavy nuclei are often unstable, so they break apart
- either independently or if a neutron is fired into the large nucleus, triggering it to break apart
- energy is released
What is the nuclide equation for nuclear fusion?
- total nucleon number is conserved
atom + neutron -> atom1 + atom2 + neutrons
Describe the mass and energy changes in nuclear fission and fusion.
they both release energy by decreasing mass slightly
How is energy released in nuclear fission/fusion?
decreasing mass slightly, typically around 0.1%
What is radioactivity?
the process by which an unstable nucleus becomes more stable
Which sources significantly contribute to background radiation?
- radon gas in air
- rocks and buildings
- food and drink
- cosmic rays