You can't directly convert "59.0" to milligrams (mg) because it's a dimensionless quantity. Milligrams are a unit of mass, and "59.0" is just a number.

To express a quantity in milligrams using scientific notation, you need a value that represents mass.

For example:

* 59.0 grams (g) in scientific notation: 5.90 x 10¹ mg

* 59.0 kilograms (kg) in scientific notation: 5.90 x 10⁷ mg

Let me know if you have a specific mass value you'd like to convert to milligrams using scientific notation.