**consider a hydrogen atom in the ground state. what is the energy of its electron? Now consider an excited- state hydrogen atom. what is the energy of the electron in the n=4 level?**

**Answer:**

for ground state : n = 1

energy E = -2.18 x 10^-18 / n^2 J

= -2.18 x 10^-18 / 1^2

**= -2.18 x 10^-18 J**

in energy level n =4

E = -2.18 x 10^-18 / n^2 J

= -2.18 x 10^-18 / 4^2

**= - 1.36 x 10^-19 J**