What is the radius of the stationary orbits $(n)$? State the formula.

(N/A) The radius of the stationary orbits is given by the formula: $r_{n} = \frac{n^{2} a_{0}}{Z} = \frac{(52.9) n^{2}}{Z} \, pm$ (for a $1$-electron system).
Where:
$n = \text{principal quantum number} = \text{orbit number} = \text{energy level} = 1, 2, 3, \dots$
$Z = \text{atomic number}$
$a_{0} = 52.9 \, pm = 0.0529 \, nm = 5.29 \times 10^{-11} \, m$ (Bohr radius).