The mass displayed by Dina's calculator, \(1.67 \times 10^{-21}\) grams, is the mass of 1000 protons. To express this mass in scientific notation for clarity, we note that:
\[ 1.67 \times 10^{-21} \]
is already in scientific notation. If you want to express it in a more standard way, it remains the same as:
\[ 1.67 \times 10^{-21} \text{ grams} \]
Therefore, the mass of 1000 protons in scientific notation is:
\[ 1.67 \times 10^{-21} \text{ grams} \]