AP EAMCET201921 Apr 2019Morning ShiftChemistryStructure of AtomActual
The energies of an electron in first orbit of He ⁺ and in third orbit of Li ²⁺ in J are respectively
Options
- A-8.72 10⁻¹⁸,-2.18 10⁻¹⁸
- B-8.72 10⁻¹⁸,-1.96 10⁻¹⁷
- C-1.96 10⁻¹⁷,-2.18 10⁻¹⁸
- D-8.72 10⁻¹⁷,-1.96 10⁻¹⁷
Correct answer
A. -8.72 10⁻¹⁸,-2.18 10⁻¹⁸
Step-by-step solution
Key Idea Use relation: E_n=-2.18 10⁻¹⁸ Z^2 n^2 ~J / ion where, E_n= energy of an electron in n th orbit Z= atomic number, n= orbit number For helium ion ( He ⁺ ) aligned Z & =2, n=1 E_n & =-2.18 10⁻¹⁸ 2^2 1^2 & =-8.72 10⁻¹⁸ ~J aligned For lithium ion ( Li ²⁺ ) aligned Z & =3, n=3 E_n & =-2.18 10⁻¹⁸ 3^2 3^2 & =-2.18 10⁻¹⁸ ~J aligned Hence, option (a) is the correct answer.