The ionization potentials for electrons in the n = 1, 2, and 3 energy levels of Pb are 1,400 x 10⁻¹⁷ J, 240 x 10⁻¹⁷J, and 48 x 10⁻¹⁷ J, respectively. When an electron in the n = 2 level fills a vacancy in the n = 1 level, what is the energy of the X-ray that is emitted?
A) 1.92 x 10⁻¹⁵ J
B ) 2.40 x 10⁻¹⁵ J
C ) 1.16 x 10⁻¹⁴ J
D ) 1.40 x 10⁻¹⁴ J