How much energy is required to excite an electron in the ground state in a hydrogen atom to the third excited state? How much more energy would it take to ionise the atom ?
1 Answer
Energy required is 12.75 eV
and 0.85 eV more to ionise the atom
Explanation:
According to Bohr's model of H atom ,
the Energy of electron in the n-th shell is given by ,
Energy required to excite from initial state to final state
Remember this always, the count of states start from one. So ground state is n=1 , first excited state is n=2 , second is n=3 ...etc.
So ,
ionising an atom means exciting the electron to the infinite excited state , so that it is no longer attached to the atom. This leaves a positive ion behind.
So you need 0.85 eV more than 12.75 eV to ionise the atom