Use the equation to answer the question.

2/1H + 2/1H -> 4/2H + energy
Which statement best describes the mass numbers of the atoms in the reaction?
• There are two atoms with mass numbers of 2
• There is one atom with a mass number of 2
• There are two atoms with mass numbers of 1
• The is one atoms with a mass number of 1

There is one atom with a mass number of 2

The statement that best describes the mass numbers of the atoms in the reaction is:

• There is one atom with a mass number of 2

To answer this question, we need to understand the equation given. The equation is showing a chemical reaction, where two hydrogen atoms combine to form a dihydrogen molecule (H2) and release energy.

Looking at the equation, we can see that there are two hydrogen atoms (H) on both sides of the equation. The symbol "2/1H" represents two hydrogen atoms, and the "2" in the numerator indicates their quantity. Similarly, the "4/2H" represents the dihydrogen molecule (H2), and the "2" in the numerator indicates their quantity.

Now, let's analyze the answer options in relation to the mass numbers of the atoms:

• Option 1: "There are two atoms with mass numbers of 2" - This is incorrect because the mass number of hydrogen is 1, not 2.

• Option 2: "There is one atom with a mass number of 2" - This is incorrect because the mass number of hydrogen is 1.

• Option 3: "There are two atoms with mass numbers of 1" - This is correct. The mass number of hydrogen is indeed 1, and there are two hydrogen atoms (H) on both sides of the equation.

• Option 4: "There is one atom with a mass number of 1" - This is incorrect because there are two hydrogen atoms.

Therefore, the statement that best describes the mass numbers of the atoms in the reaction is: "There are two atoms with mass numbers of 1."