Question

The ionic enthalpy of hydrogen atom is $1.312\times {10}^6$ $Jmo{l}^{-1}$. The energy required to excite the electron in the atom from $n_1=1$ to $n_2=2$ is:

• A. $8.51\times {10}^{5}Jmo{l}^{-1}$
• B. $6.56\times {10}^{5}Jmo{l}^{-1}$
• C. $7.56\times {10}^{5}Jmo{l}^{-1}$
• D. $9.84\times {10}^{5}Jmo{l}^{-1}$

Answer 1

The correct option is D $9.84\times {10}^{5}Jmo{l}^{-1}$

$E_2=\frac{-1.32\times {10}^6\times (1{)}^2}{2^2}$

$=-3.28\times {10}^{5}J/mol$

$E_1=-1.312\times {10}^{6}J/mol$

$\Delta E=E_2-E_1=-3.28\times {10}^5-(-13.2\times {10}^6)$

$=9.84\times {10}^{5}Jmo{l}^{-1}$