What is the Largest Quantum Number for Li3+ with a 60 Å Orbital Radius?

[hassony]

TL;DR Summary: Quantum number of a state

What is the largest quantum number of a state of the Li3+ ion with an orbital radius equal to 60 A?

I tried solving the question as below

 

[Vanadium 50]

Apart from belonging in the homework section, Li³⁺ is a bare nucleus. It has no electrons.

 

[kuruman]

Apart from Li³⁺ being a bare nucleus, $\sqrt{\dfrac{60\times 3}{0.529}}=18$ or $20$ to one sig. fig.