Throughout this book, you will find space-filling molecular models to represent molecules. Which number is the best estimate for the scaling factor used in these models? In other words, by approximately what number would you have to multiply the radius of an actual oxygen atom to get the radius of the sphere used to represent the oxygen atom in the water molecule shown here?

(a) 10 

(b) 10⁴ 

(c) 10⁸ 

(d) 10¹⁶