Question

The ionization enthalpy of a hydrogen atom is 1.312 $\times {10}^{6}J/mol$. The energy required to excited electron in an atom from n=1 to n=2 is:

• A. 7.56 $\times {10}^{5}J/Mmol$
• B. 9.84 $\times {10}^{5}J/Mmol$
• C. 8.51 $\times {10}^{5}J/Mmol$
• D. 6.56 $\times {10}^{5}J/Mmol$

Answer 1

The correct option is B 9.84 $\times {10}^{5}J/Mmol$

Energy of electron in first orbit $=E_1=-1312kJ/mol$

Energy of electron in secondorbit $=E_2=-\frac{1312}{2^2}=-328kJ/mol$

Hence, Energy required to excite a hydrogen electron from n=1 to n=2 $=E_2-E_1=-328-(-1312)=984kJ/mol$

Hence B is the correct answer