To determine how many times more grams an atom of plutonium is than an atom of hydrogen, we can use the following formula:
\[ \text{Factor} = \frac{\text{Mass of Plutonium}}{\text{Mass of Hydrogen}} \]
Given:
- Mass of hydrogen atom = \(1.67 \times 10^{-24}\) grams
- Mass of plutonium atom = \(4.05 \times 10^{-22}\) grams
Now we can substitute the values into the formula:
\[ \text{Factor} = \frac{4.05 \times 10^{-22}}{1.67 \times 10^{-24}} \]
Calculating the above gives:
\[ \text{Factor} = 4.05 \div 1.67 \times 10^{-22 + 24} = 4.05 \div 1.67 \times 10^{2} \]
Now, performing the division:
\[ 4.05 \div 1.67 \approx 2.43 \]
So,
\[ \text{Factor} \approx 2.43 \times 10^{2} \]
Therefore, an atom of plutonium is approximately \(2.43 \times 10^{2}\) times more massive than an atom of hydrogen.
The correct answer is: A. \(2.43 \times 10^{2}\).