nuclear chemistry - decay and half life
1.)__C___ Nuclear reactions involve changes in an atom’s number of
a.) protons c.) Both a and b
b.) neutrons d.) Neither a nor b
2.)__D___ The combining of two small nuclei to transform into one larger nucleus is called
a.) Synthesis b.) Junction c.) Fission d.) Fusion
3.)__B___ The heaviest of the three isotopes of hydrogen has the isotopic symbol 3H. How many neutrons are there in every atom of this isotope?
a.) one b.) two c.) three d.) zero
4.)__C___ Some isotopes are radioactive because they
a.) have too many or too few electrons outside their nucleus
b.) have too many or too few electrons inside their nucleus
c.) have too many or too few neutrons in their nucleus
d.) have too many or too few neutrons outside their nucleus
5.)__B___ When Uranium-238 undergoes an alpha decay the other product is
a.) Neptunium – 238 b.) Thorium – 234 c.) Plutonium – 242 d.) Protactinium - 238
6.)__A___ Which of the following is NOT consistent with the three types of radioactive decay.
a.) alpha particles are negatively charged and are highly penetrating
b.) Beta particles are negatively charged and are somewhat penetrating
c.) gamma radiation is electromagnetic energy (light) and has no charge and no mass
d.) Beta particles are high energy electrons that may be produced by the decay of neutrons
7.)__D___ The radioactive decay types arranged in order from MOST penetrating to LEAST penetrating is
a.) Gamma > Alpha > Beta c.) Beta > Gamma > Alpha
b.) Alpha > Beta > Gamma d.) Gamma > Beta > Alpha
8.)__A___ The decay that would remove the most mass from an unstable nucleus is:
a.) alpha decay b.) beta decay c.) positron decay d.) no difference
9.)__A___ The particle needed to balance the nuclear equation 231Th → _______ + 231Pa is
a.) e- b.) 4He c.) e+ d.) 1H
10.)__A__ Nuclear stability depends on the
a.) neutron : proton ratio c.) proton : electron ratio
b.) neutron : electron ratio d.) electron : mass number ratio
11.) The half-life of radioactive isotope is 10 days. A 320 gram is stored for 60 days before being used.
How many half-lives have gone by? ___________six________________ half-lives.
How many grams remain of the original isotope? __________5__________________ grams.
Examine the diagram to the right
and identify the radioactive decay
particle as either
Alpha, Beta, or Gamma radiation.
12.)_gamma____________________________
13.)__beta___________________________
14.)___(actually 11) alpha__________________________
15.) Determine the ½-life of Californium – 252 using the graph below.
The half-life of Californium – 252 is ___2.7__________ years.
16 – 20.) Balancing and Identifying Nuclear Equations
16.) 236Th → ___0-1e________ + 236Pa beta decay
17.) 5Be + 4He → 1n + ___76C_______ artificial transmutation
18.) 235U + 1n → 90Sr + ___14354Xe_______ + 3 1n fission
19.) 2H + 4He → ___10n____ + 5Li fusion
20.) Identify each equation above as fission, fusion, natural transmutation, or artificial transmutation.