Question

Arrange $4d,5p,5f$ and $6p$ orbitals in decreasing order of their energies:

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• A. $6p>5f>5p>4d$
• B. $6p>5f>4d>5p$
• C. $5f>6p>5p>4d$
• D. $5f>6p>4d>5p$

Answer 1

The correct option is C $5f>6p>5p>4d$

Higher the $n+l$ value, higher id the energy.
$(n+l)$ values for :
$4d=4+2=6$
$5p=5+1=6$
$5f=5+3=8$
$6p=6+1=7$
If $(n+l)$ values are same, then higher value of n will have more energy. So, 5p has more energy than 4d
∴ Correct order of energy would be $5f>6p>5p>4d$
Correct option is A