Chapter 11 & 12 Flashcards
What two types of particles does the nucleus contain?
Protons & Neutrons
The number of protons in the nucleus is given by…
the atomic number, Z.
The neutron number, N, is the…
number of neutrons contained in a nucleus.
The mass number, A, is the…
total number of protons and neutrons in a nucleus.
Protons and neutrons are collectively referred to as
nucleons
_______ of a given element have the same number of protons in the nucleus but a different number of neutrons.
Isotopes
The 4 fundamental forces
1) Gravity -binds planets to the sun
2) Electromagnetic Force - binds atoms and molecules
3) Weak nuclear force - produces beta decay
4) Nuclear Strong Force - binds the nucleus.
Isotopes with unstable nuclei are called
radioisotopes
Radioactivity, also called radioactive decay, occurs when…
an unstable nucleus emits radiation.
_______ is helium-4 nuclei.
alpha radiation
_______ is high energy electrons.
beta radiation
_______ is EM radiation.
gamma radiation
when an unstable nucleus ejects a helium nucleus, two protons and two neutrons.
Alpha decay occurs
When an unstable nucleus ejects an electron.
Beta decay occurs
When an excited nucleus ejects a photon.
Gamma decay occurs
List the types of radiation in order of least difficult to stop to most difficult to stop.
alpha, beta, gamma
Which type of radiation is most difficult to stop?
Gamma radiation
When does radioactive decay occur?
Spontaneously
At random
But predictably – like how many times you get 11 after thousands of rolls.
The time it takes for half the nuclei in a sample of a radioisotope to decay.
Half-life
______ uses the decay-rate of carbon-14 to determine how long ago an organism died.
Carbon-14 dating
_______ is naturally created when thermal neutrons in the upper atmosphere bombard N-14.
C-14
Considered the fatal dose of radiation.
6 Sv or Gy
Something harmful at high doses is beneficial at low doses.
hormesis
Implant Radiation Therapy. Radioactive “seeds” placed directly into a cancer tumor.
Brachytherapy
