Use the equation to answer the question.

Question

21H+ 21H→ 42H+energy
1
2
H
+

1
2
H
→

2
4
H
+
energy

Which statement best describes the mass numbers of the atoms in the reaction?

(1 point)
Responses

There are two atoms with mass numbers of 2.
There are two atoms with mass numbers of 2.

There is one atom with a mass number of 1.
There is one atom with a mass number of 1.

There is one atom with a mass number of 2.
There is one atom with a mass number of 2.

There are two atoms with mass numbers of 1.

Answer 1

To analyze the given equations:

1. The first equation indicates that two hydrogen atoms (21H) combine to form a helium atom (42H) and energy is released. The mass number for each hydrogen atom (21H) is 2, resulting in a total mass number of 4 for the product (42H).

2. The second equation also indicates a fusion reaction where two hydrogen isotopes (1/2H) combine to form a helium nucleus (2/4H). In this case, each hydrogen isotope has a mass number of 2.

From this analysis, we can see:

• In the first equation, there are two atoms with a mass number of 2.
• In the second equation, there is one atom with a mass number of 2.

Therefore, the best description of the mass numbers of the atoms in the reaction, based on both equations together, is:

There are two atoms with mass numbers of 2.