Question

Two statements are given below: Statement I: In H atom, the energy of 2s and 2p orbitals is the same. 
Statement II: In He atom, the energy of 2s and 2p orbitals is the same. 

• A. Both statements I and II are correct
• B. Both statements I and II are not correct
• C. Statement I is correct but statement II is not correct
• D. Statement I is not correct but statement II is correct

Hint:

In single-electron atoms (like hydrogen), the energy of orbitals depends only on the principal quantum number (\( n \)). In multi-electron atoms (like helium), electron-electron interactions cause energy splitting among orbitals with the same \( n \) but different \( l \).

Answer 1

The Correct Option is C

Step 1: Energy Levels in a Hydrogen Atom 
For a hydrogen atom (\( H \)), the energy of orbitals depends only on the principal quantum number (\( n \)) and not on the azimuthal quantum number (\( l \)). This means: \[ E_{2s} = E_{2p} \] Thus, in a hydrogen atom, the energy of the 2s and 2p orbitals is the same, making Statement I correct. 

Step 2: Energy Levels in a Helium Atom 
For a helium atom (\( He \)), there is electron-electron interaction in addition to the nuclear attraction. Due to this, the energy of orbitals with the same principal quantum number (\( n \)) but different azimuthal quantum numbers (\( l \)) differs: \[ E_{2s} \neq E_{2p} \] Thus, in a helium atom, the energy of the 2s and 2p orbitals is not the same, making Statement II incorrect.

 Step 3: Verify the Correct Answer 
Since Statement I is correct and Statement II is incorrect, the correct answer is Option (3).