Question

If the energy of the electron in the first orbit of $H-$ atom is $E$, then the energy of the electron in the first Bohr orbit of $L{i}^{2+}$ ion is:

• A. $4E$
• B. $9E$
• C. $3E$
• D. $2E$

Answer 1

The correct option is B $9E$

$Energy\propto \frac{Z^2}{n^2}$

For $L{i}^{2+}$, the number of electrons is 1. Thus, orbit number $n=1$.

Also, for Li the atomic number$Z=3$.

Thus, Energy in the first Bohr orbit of $L{i}^{2+}=(3{)}^{2}E=9E$