A Hydrogen Atom with a Barely Bound Electron May Have $14 \mu \mathrm { m } .$

Multiple Choice

A hydrogen atom with a barely bound electron may have an average radius as large as a bacterium, which is a radius of $14 \mu \mathrm { m } .$ What is the nearest principal quantum number of the atom in this state? The radius for ground state hydrogen is 0.0529 nm.

A) 514
B) 51
C) 16
D) 264,650