Final answer:
The energy of the n=4 energy level in a hydrogen atom is -0.85 eV, and to ionize an electron from this level, 0.85 eV is needed because ionization energy is the absolute value of the electron's energy.
Step-by-step explanation:
When considering an electron in the n=4 energy level of a hydrogen atom, it is important to understand that the energy levels of electrons in an atom are quantized. This means that they can exist only at certain discrete energy levels, defined by the principal quantum number n. The energy level of an electron is given by the equation En = -13.6 eV / n2, where n is the principal quantum number and the energy for the ground state (n=1) is -13.6 eV.
For an electron in the n=4 level, the energy is calculated as follows: E4 = -13.6 eV / 42 = -13.6 eV / 16. This results in an energy of -0.85 eV for the n=4 energy level. To ionize an electron from this energy level, we would need to provide enough energy to bring it to zero potential energy. Therefore, the ionization energy required would be the absolute value of the electron's energy in the n=4 level, which is 0.85 eV.