the ground stste energy of H- atom is -13.6 eV. the energy needed to ionise H- atom from its second excited state is
1.51 eV
3.4 eV
13.6 eV
12.1 eV
To find the energy needed to ionize the H- atom from its second excited state, we need to know the energy levels of the H- atom. The energy levels of the hydrogen atom can be calculated using the Rydberg formula:
E_n = -13.6 eV / n^2
Where E_n is the energy of the hydrogen atom at the nth energy level, and n is the principal quantum number.
In the case of the H- atom, the ground state energy is given to be -13.6 eV. This corresponds to n = 1.
For the second excited state, we need to find the value of n. To determine this, we can use the fact that the energy levels are given by n = 1, 2, 3, ...
Thus, the second excited state corresponds to n = 3.
Plugging in n = 3 into the Rydberg formula, we get:
E_3 = -13.6 eV / (3^2) = -13.6 eV / 9 ≈ -1.51 eV
Therefore, the energy needed to ionize the H- atom from its second excited state is approximately 1.51 eV.
Therefore, the correct answer is 1.51 eV.