How much energy is required to ionise an H atom if the electron occupies n = 5 orbit? Compare your answer with the ionization enthalpy of H atom. - Chemistry

Advertisements
Advertisements
Numerical

How much energy is required to ionise an H atom if the electron occupies n = 5 orbit? Compare your answer with the ionization enthalpy of H atom (energy required to remove the electron from n =1 orbit).

Advertisements

Solution

The expression of energy is given by,

`"E"_"n" = (-(2.18xx10^(-18))"Z"^2)/"n"^2`

Where,

Z = atomic number of the atom

n = principal quantum number

For ionization from n1 = 5 to `"n"_2 = ∞`

`triangle "E" = "E"_(∞) -  "E"_5`

`=[{{-(2.18xx10^(-18)J)(1)^2)/(∞)^2}-{(-(2.18xx10^(-18)J(1)^2))/(5)^2}]`

`= (2.18xx10^(-18)"J")(1/((5)^2))      ("Since" 1/∞ = 0)`

`= 0.0872 xx 10^(-18) "J"`

`triangle "E" = 8.72 xx 10^(-20) "J"`

Hence, the energy required for ionization from n = 5 to n = ∞ is 8.72 × 10–20 J.

Energy required for n1 = 1 to n = ∞

`triangle "E'" = "E"_(∞) - "E"_1`

`= [{(-(2.18xx10^(-18))(1)^2)/(∞)^2}-{(-(2.18xx10^(-18))(1)^2)/(1)^2}]`

`= (2.18 xx 10^(-18)) [1 - 0]`

`= 2.18 xx 10^(-18) "J"`

Hence, less energy is required to ionize an electron in the 5th orbital of hydrogen atom as compared to that in the ground state.

  Is there an error in this question or solution?
Chapter 2: Structure of Atom - EXERCISES [Page 70]

APPEARS IN

NCERT Chemistry Part 1 and 2 Class 11
Chapter 2 Structure of Atom
EXERCISES | Q 2.14 | Page 70
Share
Notifications



      Forgot password?
Use app×