If you wanted to make an accurate scale model of the hydrogen atom and decided that the nucleus would have a diameter of 1mm, what would be the diameter of the entire model?

The diameter of the model would be 63.1 m.

The diameter of a hydrogen atom is 1.06 × 10⁻¹⁰ m.
The diameter of a proton is 1.68 × 10⁻¹⁵ m.

The ratio of their diameters is = 6.31 × 10⁴

So the diameter of your model would be 6.31 × 10⁴ mm
.
6.31 × 10⁴ mm × = 63.1 m