How much energy is needed to completely remove an electron from n = 2 in a hydrogen atom?
E = 2.180E-18(1/2^2) joules.
To calculate the energy needed to completely remove an electron from the n = 2 energy level in a hydrogen atom, we need to use the formula for the energy of an electron in a hydrogen atom:
E = -13.6 / n^2 electron volts (eV)
In this case, n = 2, so substituting it into the formula:
E = -13.6 / 2^2 eV
= -13.6 / 4 eV
= -3.4 eV
So the energy needed to completely remove an electron from the n = 2 energy level in a hydrogen atom is 3.4 electron volts (eV).