Nuclear Physics Flashcards
The atom
Protons and neutrons are in the nucleus and are referred to as nucleons. They both have equal mass.
Proton
Particle in nucleus of atoms with a relative charge of +1
Neutron
Particle in nucleus of atoms with a relative charge of 0
Electrons
Relative charge of -1
If a particle looses electrons
Becomes positively charged
If a particle gains electrons
Becomes negatively charged
How do we represent nuclei:
A
C
Z
A: mass number or nucleon number = protons+neutrons
Z: atomic number or proton number= protons
Isotopes
Atoms of the same element that have the same number of protons and different number of neutrons.
Fission
Splitting a bigger nuclei into two smaller ones
-every time there is fission, energy is released
Fusion
Two smaller nuclei being joined to form a bigger one
-energy is also released
Radioactivity, how is it detected
-using a Geiger counter, measured in counts/s
Background radiation
Measures the level of ionizing radiation present in the environment at a specific location.
Examples of sources of background radiation
-food and drinks
-cosmic rays
-man made sources
Three types of nuclear emission
1) Alpha emission α (very high ionizing power)
2) Beta emission β (intermediate)
3) Gamma emission γ (very low)
Alpha emission
Nature: helium nucleus of 2 protons and 2 neutrons
-In nuclear equations mass and charge have to be balanced out.
-deflects upwards
Beta emissions
- β- = electron
- deflects downwards
0 0
B = e-
-1 -1
-In Beta minus emission, a neutron turns into a proton emitting an electron.
Gamma emission
0 (no mass)
γ
0 (no charge)
-neutral
-radiation to release excess of energy normally after alpha and beta emissions.
-deflects in a straight (neutral) line
Radioactive decay
-emission of ionizing radiation by unstable nuclei
- “decay”: transform into something else by emitting ionizing radiation
-Random and spontaneous
-if a nucleus has too many neutrons it will be unstable.
-Isotopes of elements may be radioactive and emit radiation if they are unstable
Half life
Time taken for half the nuclei of a radioactive sample to decay
Safety precautions
-protective suits: absorb radiation
-radioactive hazard labels: warn people about danger to stay safe
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