I know that [tex]\[
R = \frac{{mv}}{{\left| q \right|B}}
\][/tex], but I am unsure how to calculate the velocity, and I certainly don't know how to calculate the charge. My educated guess is that velocity and charge are directly proportional over a potential difference so that they don't matter in this problem, but I don't have any equations relating the three.

Well, in the case of an atom, or more precisely, ion, singly charged usually means a single + charge (i.e. it has one less electron than the neutral atom).

The velocity can be determined from the kinetic energy, which is equal to the energy received from being accelerated (assume from rest) across a potential difference (229 V). One unit charge 'q' or 'e' is receives 1 eV of energy from a 1 V potential.