CHEM120 CERTIFICATION EVALUATION
2026 COMPLETE ANSWERS GRADED A+
⩥An proton absorbs an electron. What effect would you predict this to
have in an unstable isotope? Answer: By understanding what is
happening on a subatomic level, we can better predict what is occurring
in unstable isotopes. If a proton absorbs an electron in an unstable
isotope, you would see a decrease in the atomic number.
⩥Sort the following types of radiation in regard to their ability to
penetrate the human body from top (most) to least (bottom). Answer:
Understanding the penetrative properties of various types of radiation
can help us make important safety choices. The most penetrating type of
radiation is gamma, while the least is alpha.
⩥If Magnesium-21 undergoes beta positron decay, I would expect the
products of this decay to be a positron and a. Answer: We see a decrease
of one for the atomic number in positron decay with no change in the
mass number.
⩥During a type of radioactive decay, the atomic number of an isotope
increases by one while the mass number is unchanged. I would expect
that this is caused by. Answer: By understanding what is happening on a
subatomic level, we can better predict what is occurring in a specific
radioactive decay process. When the atomic number increases by one
while the mass number is unchanged, a neutron has become a proton.
,⩥171^ 80 Hg
undergoes alpha decay forming an alpha particle and. Answer: We can
determine the effect on the decay product by following the Law of
Conservation of Mass. When
171/80Hg
undergoes alpha decay, an alpha particle and
167/78Pt
is formed.
⩥Determine the products of the beta electron decay of Vanadium-52
(select all that apply): 52/23 V. Answer: Beta decay increases the atomic
number by 1.
⩥Select all processes which cause a decrease in the atomic number of an
isotope.. Answer: The main ways to decrease atomic number are the
removal of protons from the nucleus or the conversion of a proton to a
neutron. This could occur via alpha decay, beta positron decay, and
electron capture.
⩥How many grams of a 4 grams sample of a radioactive material will
remain after two half-lives.. Answer: Each half-life decreases the amount
currently remaining by 50%, so after two half-lives, 4 grams would be 1
gram.
, ⩥Which of the following technologies depend on radioactive isotopes to
function. Select all that apply.. Answer: PET scans and nuclear power
generation both require radioactive isotopes to function.
⩥Half Life. Answer: In nuclear chemistry, half life is a measure of how
much time is required for the radioactivity of a specific radioactive
material to decrease to half the original value. As we explored earlier,
unstable isotopes decay over time. Some radioactive isotopes decay
more quickly than others, and thus a wide range of half life values are
possible, from infinitesimal fractions of a second to longer then the
current age of the universe.
Radioactive isotopes decay using one or more of the radioactive decay
types you have studied. These processes occur over time and if we know
the half life of a given radioactive material, we can predict how much of
that material will still be radioactive after a given period of time.
Radioactive Iodine-131, an isotope frequently used in healthcare, has a
half life of 8 hours. This results in the radioactivity of Iodine-131
decreasing by half of its current value every 8 hours. As you see, this
results in an exponential decrease in the radioactivity of this material
over time. Please note the dotted line indicating the trend of this decay.
This chart also shows us that after 16 hours, two half-lives have
occurred, meaning that this sample only has 25% of the original
radioactivity after this period of time.
2026 COMPLETE ANSWERS GRADED A+
⩥An proton absorbs an electron. What effect would you predict this to
have in an unstable isotope? Answer: By understanding what is
happening on a subatomic level, we can better predict what is occurring
in unstable isotopes. If a proton absorbs an electron in an unstable
isotope, you would see a decrease in the atomic number.
⩥Sort the following types of radiation in regard to their ability to
penetrate the human body from top (most) to least (bottom). Answer:
Understanding the penetrative properties of various types of radiation
can help us make important safety choices. The most penetrating type of
radiation is gamma, while the least is alpha.
⩥If Magnesium-21 undergoes beta positron decay, I would expect the
products of this decay to be a positron and a. Answer: We see a decrease
of one for the atomic number in positron decay with no change in the
mass number.
⩥During a type of radioactive decay, the atomic number of an isotope
increases by one while the mass number is unchanged. I would expect
that this is caused by. Answer: By understanding what is happening on a
subatomic level, we can better predict what is occurring in a specific
radioactive decay process. When the atomic number increases by one
while the mass number is unchanged, a neutron has become a proton.
,⩥171^ 80 Hg
undergoes alpha decay forming an alpha particle and. Answer: We can
determine the effect on the decay product by following the Law of
Conservation of Mass. When
171/80Hg
undergoes alpha decay, an alpha particle and
167/78Pt
is formed.
⩥Determine the products of the beta electron decay of Vanadium-52
(select all that apply): 52/23 V. Answer: Beta decay increases the atomic
number by 1.
⩥Select all processes which cause a decrease in the atomic number of an
isotope.. Answer: The main ways to decrease atomic number are the
removal of protons from the nucleus or the conversion of a proton to a
neutron. This could occur via alpha decay, beta positron decay, and
electron capture.
⩥How many grams of a 4 grams sample of a radioactive material will
remain after two half-lives.. Answer: Each half-life decreases the amount
currently remaining by 50%, so after two half-lives, 4 grams would be 1
gram.
, ⩥Which of the following technologies depend on radioactive isotopes to
function. Select all that apply.. Answer: PET scans and nuclear power
generation both require radioactive isotopes to function.
⩥Half Life. Answer: In nuclear chemistry, half life is a measure of how
much time is required for the radioactivity of a specific radioactive
material to decrease to half the original value. As we explored earlier,
unstable isotopes decay over time. Some radioactive isotopes decay
more quickly than others, and thus a wide range of half life values are
possible, from infinitesimal fractions of a second to longer then the
current age of the universe.
Radioactive isotopes decay using one or more of the radioactive decay
types you have studied. These processes occur over time and if we know
the half life of a given radioactive material, we can predict how much of
that material will still be radioactive after a given period of time.
Radioactive Iodine-131, an isotope frequently used in healthcare, has a
half life of 8 hours. This results in the radioactivity of Iodine-131
decreasing by half of its current value every 8 hours. As you see, this
results in an exponential decrease in the radioactivity of this material
over time. Please note the dotted line indicating the trend of this decay.
This chart also shows us that after 16 hours, two half-lives have
occurred, meaning that this sample only has 25% of the original
radioactivity after this period of time.
