Find the mass of this ion moving in a magnetic field

[Bolter]

Homework Statement

See below

Relevant Equations

F = Bqv
F = mv^2/r

I had started off by equating the magnetic force to the centripetal force, to find the mass of a single ion. Then calculated the mass of what 1 mole of that ion would weigh to identify what the ion is

Hence the answer would be nitrogen (option C) as 1 mole of nitrogen weighs 14g
Would this be the right way of going about it?

Thanks for any help!

 

[Cutter Ketch]

Looks fine to me

 

[Bolter]

Looks fine to me

Ok thank you, was getting different values beforehand but I believe I must have type the numbers in incorrectly into the calculator