Radioactive Decay and Isotopes Exploration
1. What is the change in atomic mass number when an atom emits an alpha particle?
A) decreases by 2
B) decreases by 4
C) decreases by 2
D) increases by 4
2. If an isotope decays by the process of beta emission __.
A) the mass number changes
B) the atomic number changes
C) protons are given off
D) the number of neutrons remains the same
3. 56/25 Mn -> __ + 0/-1 e
A) 56/27 Co
B) 37/25 Mn
C) 56/26 Fe
D) 58/24 Cr
4. Which of the following naturally occurring radioisotopes would be most useful in dating objects though to be a million years old?
A) carbon-14; t1/2=5.73x10^3
B) potassium-40; t1/2=1.28x10^9
C) thorium-23; t1/2=25 days
D) radon-222; t1/2=3.8 days
5. The production of carbon-14 __.
A) takes place in the upper atmosphere
B) is mostly due to fallout from nuclear explosions
C) occurs to a large extent in nuclear reactors
D) is caused by photosynthesis in plants
Answers:
1. Decreases by 4. (B)
2. The atomic number changes. (B)
3. 56/26 Fe. (C)
4. Potassium-40; t1/2=25 days. (B)
5. Takes place in the upper atmosphere. (A)
Exploring Radioactive Decay and Isotopes
Radioactive decay is a fascinating process in which unstable atoms transform into more stable forms by emitting particles or energy. In the case of alpha decay, an atom emits an alpha particle consisting of two protons and two neutrons. This results in a decrease of 4 in the atomic mass number.
On the other hand, beta decay involves the emission of a beta particle, which is an electron or positron. This process leads to a change in the atomic number of the atom while the mass number remains the same.
In the specific example of 56/25 Mn decaying into 56/26 Fe by emitting a beta particle, the atomic number of the manganese atom increases by 1 to become iron.
When it comes to dating objects, potassium-40 is the most useful naturally occurring radioisotope for objects thought to be a million years old. With a half-life of 1.28x10^9 years, it provides a reliable method for determining the age of such ancient artifacts.
Lastly, the production of carbon-14 mainly takes place in the upper atmosphere through the interaction of cosmic rays with nitrogen atoms. This radioactive isotope is essential in carbon dating archaeological finds and estimating the age of organic materials.