JEE Main2010ChemistryStructure of AtomActual
Ionisation energy of He ⁺ is 19.6 10⁻¹⁸ ~J atom ⁻¹ . The energy of the first stationary state ( n =1) of Li ²⁺ is
Options
- A4.41 10⁻¹⁶ ~J atom ⁻¹
- B-4.41 10⁻¹⁷ ~J _ atom ⁻¹
- C-2.2 10⁻¹⁵ ~J atom ⁻¹
- D8.82 10⁻¹⁷ ~J _ atom ⁻¹
Correct answer
B. -4.41 10⁻¹⁷ ~J _ atom ⁻¹
Step-by-step solution
IE _ He ⁺ =13.6 Z _ He ⁺ ^2 [ 1 1^2 - 1 ^2 ]=13.6 Z _ He ⁺ ^2 where ( Z _ He ⁺ =2 ) Hence 13.6 Z_ He ⁺ ^2=19.6 10⁻¹⁸ ~J atom ⁻¹ . ( E ₁ )_ L ⁺² =-13.6 Z _ Uj ⁺² ^2 1 1^2 =-13.6 Z _ He ⁺ ^2 [ Z _ L ⁺² ^2 Z _ He ⁺ ^2 ]=-19.6 10⁻¹⁸ 9 4 =-4.41 10⁻¹⁷ ~J / atom