Question

The energy required to excite the electron in the atom from $n=1$ to $n=2$, when the ionization enthalpy of a hydrogen atom is $1.312\times {10}^{6}J/mol$ will be:

(in the unit of ${10}^5$ ).

• A. 8.53
• B. 7.51
• C. 8.92
• D. 9.86

Answer 1

The correct option is D 9.86

$E_2=\frac{-1.312\times {10}^6\times (1{)}^2}{(2{)}^2}$

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

Given that,

$I.E.=E_{\infty }-E_1$

$1.312\times {10}^6=0-E_1$

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

$\therefore \Delta E=E_2-E_1$

$=-3.28\times {10}^5-(-1.312\times {10}^6)$

$=9.86\times {10}^{5}J/mol$

Hence, the correct option is $D$