Complete each nuclear reaction.
${ }_2^2 H+{ }_2^2 H \rightarrow{ }_2 He+{ }_0^1 n$
${ }_{92}^{238} U \rightarrow{ }^{F} Th+{ }_2^8 He$
D: $\square$ F: $\square$
E: $\square$ G: $\square$
Answer (1)
Conserve mass number: In the first reaction, 2 + 2 = E + 1 , so E = 3 .
Conserve atomic number: In the first reaction, 1 + 1 = D + 0 , so D = 2 .
Conserve mass number: In the second reaction, 238 = F + 4 , so F = 234 .
Conserve atomic number: In the second reaction, 92 = G + 2 , so G = 90 .
The completed reactions involve 2 3 He and 90 234 T h , thus the final answer is D = 2 , E = 3 , F = 234 , G = 90 .
Explanation
Understanding Nuclear Reactions We are given two nuclear reactions to complete. In a nuclear reaction, both the mass number (the superscript) and the atomic number (the subscript) must be conserved. This means the sums of the mass numbers and the atomic numbers must be the same on both sides of the equation.
Completing the First Reaction For the first reaction, we have 2 2 H + 2 2 Hr i g h t a rro w D E He + 0 1 n We need to find the values of D and E. The sum of the mass numbers on the left side is 2 + 2 = 4. On the right side, it is E + 1. Therefore, E + 1 = 4, so E = 3. The sum of the atomic numbers on the left side is 1 + 1 = 2. On the right side, it is D + 0. Therefore, D = 2.
Completing the Second Reaction For the second reaction, we have 92 238 U r i g h t a rro w G F T h + 2 4 He We need to find the values of F and G. Note that the Helium should have a mass number of 4, not 8. The sum of the mass numbers on the left side is 238. On the right side, it is F + 4. Therefore, F + 4 = 238, so F = 234. The sum of the atomic numbers on the left side is 92. On the right side, it is G + 2. Therefore, G + 2 = 92, so G = 90.
Final Answer Therefore, the completed reactions are: 2 3 He 90 234 T h So, D = 2, E = 3, F = 234, and G = 90.
Examples
Nuclear reactions are fundamental in understanding the energy production in stars and the creation of elements. For example, the fusion of hydrogen isotopes into helium releases tremendous energy, powering the sun. Similarly, radioactive decay, like the alpha decay of uranium, is used in various applications, including radioactive dating to determine the age of rocks and artifacts. Understanding these reactions helps us harness nuclear energy and explore the history of the universe.
