A carbon atoms weights 1.99 x 10^-26 kg, and a helium atom weights 6.65 x 10^-27 kg. How many times heavier is an atom of carbon than an atom of helium? Round to the nearest whole number.

1. Weight of a carbon atom: 1.99 \times 10^{-26} kg

2. Weight of a helium atom: 6.65 \times 10^{-27} kg

3. Divide the weight of the carbon atom by the weight of the helium atom:

\frac{1.99 \times 10^{-26}}{6.65 \times 10^{-27}}

4. Calculate the ratio:

\frac{1.99}{6.65} \times \frac{10^{-26}}{10^{-27}} = \frac{1.99}{6.65} \times 10^{1}

5. Simplify the fraction:

\frac{1.99}{6.65} \approx 0.2992

6. Multiply by 10^{1} to shift the decimal place:

0.2992 \times 10 = 2.992

7. Round to the nearest whole number:

\approx3

Thus, an atom of carbon is approximately 3 times heavier than an atom of helium.