To express the mass of 1,000 protons in scientific notation, we start with the value given by Dina's calculator, which is \(1.67 \times 10^{-21}\) grams.
To find the mass of 1,000 protons, we first need to identify the mass of a single proton. The mass of one proton is approximately \(1.67 \times 10^{-27}\) grams.
Now, to find the mass of 1,000 protons, we multiply the mass of one proton by 1,000:
\[ \text{Mass of 1,000 protons} = 1000 \times (1.67 \times 10^{-27}) \]
\[ = 1.67 \times 10^{-27} \times 10^3 \] \[ = 1.67 \times 10^{-24} \text{ grams} \]
Therefore, in scientific notation, the mass of 1,000 protons is:
\[ 1.67 \times 10^{-24} \text{ grams} \]
In your notation, the answer would thus be:
\[ 1.67 \times (10^{-24}) \text{ grams} \]
So the blank would be filled with \(-24\).