An electron jumps down from the fourth energy level to the first energy level and releases a light wave of 10.8 nm in wavelength. Determine the energy level value for the fourth energy level for the atom

-20.2  * 10^-18 J

Explanation:

From;

E = hc/λ

h= planks constant = 6.6 * 10^-34 Js

c= speed of light = 3 * 10^8 ms-1

λ = wavelength = 10.8 * 10^-9 m

Substituting values;

E = 6.6 * 10^-34 * 3 * 10^8/ 10.8 * 10^-9

ΔE = -1.8 * 10^-17 J

But for ground state  E1=−13.6eV or -2.176 * 10^-18 J

From;

ΔE = E4 - E1

E4 = ΔE + E1

E4 =  (-1.8 * 10^-17) + (-2. 176* 10^-18)

E4 = -20.2  * 10^-18 J

the answer for sodium is 0.186

the answer for rubidium is 0.251