nuclear transformations

amount of energy required to hold a nucleus together

nuclear binding energy

nuclear binding energy is measured in

MeV

if the atoms are higher than ground ground state the nucleus is

unstable

if atoms are at ground state the nucleus is

stable

minimum amount of energy required to maintain stability

ground state

the emission of energy from nucleus in the form of EM or particulate radiation as means of returning to ground state

radioactivity

Refers to the tendency of a nucleus of an atom to decay

nuclear stability

Neutron‐to‐Proton ratio predicts

nuclear stability

Elements with a low Z# (30 or below) are stable when there is a __:1 ratio

1

Elements with a high Z# (31‐82) are stable when there is a ____:1 ratio

1.5

Elements with a Z# above 82 are

unstable (radioactive)

if there is an even amount of protons and neutrons it is considered

stable (most stable)

if there is an odd amount of protons and neutrons it is considered

unstable (least stable)

which is more stable: odd number of protons and even number of neutrons or even number of protons and odd number of neutrons

even proton, odd neutron

Graphic representation of atomic stability based on atomic number

nuclear stability curve

nuclear stability curve is the “line of ______”

stability

A condition when both parent and daughter are radioactive and when the daughter’s half-life is shorter than that of the parent

radioactive equilibrium

Half life of parent slightly greater than that of decay product (> 10 times)

transient equilibrium

Half‐life of parent much greater than (> 100 times) that of decay product

secular equilibrium

Half‐life of parent less than that of decay product

no equilibrium

Results from unstable radioactive isotopes and the nucleus breaks apart

radioactive decay

what are the 3 primary modes of decay

alpha emission, beta emission, and electromagnetic decay (other modes: electron capture and internal conversion)

Radioactive, unstable nucleus emits 2 protons and 2 neutrons (alpha particle) to become more stable

alpha particle emission

alpha particles have ____ LET radiation

high

charge of alpha particles

+2

T/F alpha particles can penetrate well

false (<1mm)

each emission of alpha particle results in a reduction in the atomic number by

2

each emission of alpha particle results in a reduction in the mass number by

4

Radioactive, unstable nucleus emits either a positron or a negatron

beta particle emission

beta particle emission that occurs with a high neutron‐to‐ proton ratio

negatron emission

beta particle emission that occurs with a high proton‐to neutron ratio

positron emission

for ____ emission the neutron decays into a proton and an electron. The proton stays in the nucleus while the electron is ejected

negatron

for ____ emission the proton converts to a neutron and a positron. The neutron stays in the nucleus and the positron is emitted

positron

T/F atomic mass changes when beta particle emission occurs

false (only atomic number)

Alternative process to positron decay

electron capture

this occurs when the nucleus consumes an inner shell orbital electron and transforms a proton into a neutron

electron capture

electron capture reduces the atomic number by

1

Nuclei in intermediate metastable are known as

isomeric states

Radioactive nuclei emits EMR in the form of gamma rays to become more ____

stable

T/F With gamma emission, atomic and mass numbers remain the same

true

MER gamma radiation is ___ LET

low

Excess nuclear energy may be transferred to an orbital electron. That orbital electron is then ejected. The vacancy is filled leading to characteristic radiation or auger electrons

internal conversion

Process in which two nuclei, or a nucleus and an external subatomic particle, collide to produce one or more nuclides

nuclear reactions

a very heavy nucleus splits to form 2 or more medium‐mass nuclei, involves a simultaneous release of energy

nuclear fission

when lightweight (low Z) nuclei combine to form a heavier more stable nuclei, involves a simultaneous release of energy

nuclear fusion

activation of nuclides is when we create artificial ____ sources

radioactive

When activating nuclides, the activity of the produced sample grows exponentially (quickly in large amounts)

growth of activity

Eventually the activation of activity equals rate of decay

saturation activity