An electron in Li²⁺ is in the n = 2 state. What is its energy in joules? (E₁ for H = -2.18 × 10⁻¹⁸ J)
E₂ = -9 × 2.18×10⁻¹⁸ / 4 = -4.905×10⁻¹⁸ J.
Ref: NCERT Class 11 Chemistry > Chapter 2: Structure of Atom > Topic: Discovery of Subatomic Particles - Electron Proton Neutron