Question

The radius of third orbit of He\(^+\) is \( Y \, \text{Å} \). The radius of second orbit of Li\(^{2+}\) (in Å) is:

• A. \( \frac{27}{4} Y \)
• B. \( \frac{27}{8} Y \)
• C. \( \frac{8}{27} Y \)
• D. \( \frac{4}{27} Y \)

Hint:

For hydrogen-like ions, radius scales as \( r \propto \frac{n^2}{Z} \). Always compare using ratios to avoid full calculation.

Answer 1

The Correct Option is C