Question

The order of increasing energies of the orbitals follows:

• A. \(5p<4f<6s<5d\)
• B. \(5p<6s<4f<5d\)
• C. \(4f<5p<5d<6s\)
• D. \(5p<5d<4f<6s\)

Hint:

If \(n+l\) is same, orbital with lower n has lower energy.

Answer 1

The Correct Option is B

Concept: Use \(n + l\) rule: \[ \text{Lower } (n+l) \Rightarrow \text{lower energy} \]

Step 1: Calculate values.
\[ 5p: n+l = 5+1=6 \] \[ 6s: 6+0=6 \] \[ 4f: 4+3=7 \] \[ 5d: 5+2=7 \]

Step 2: Tie-breaking.
Lower \(n\) → lower energy: \[ 5p<6s \] \[ 4f<5d \]

Step 3: Final order.
\[ 5p<6s<4f<5d \]