Question

Calculate the ratio of energies of 2nd orbits of hydrogen, $H{e}^{+},L{i}^{+2}$.

• A. 1 : 2 : 3
• B. 1 : 4 : 9
• C. 4 : 3: 9
• D. none of these

Answer 1

The correct option is B 1 : 4 : 9

Energy of electrons in hydrogen - like species.

$-13.6\frac{Z^2}{n^2}$ eV

Ratio of energies of 2nd orbit H, $H{e}^{+}$, $L{i}^{2+}$

$=\frac{-13.6(1{)}^2}{(2{)}^2}$ : $=\frac{-13.6(2{)}^2}{(2{)}^2}$ : $=\frac{-13.6(3{)}^2}{(2{)}^2}$

1:4:9 is required ratio.