. 4d,5p,5f and 6p orbitals are arranged in the order of decreasing energy

Best Answer

Correct Option is :(b)

Higher the value of (n+l) for an orbital, higher is its energy. 

But if in any case, two different types of orbitals have same value of (n+l), the orbital with lower value of principal quantum number (n) has lower energy. 

(n+l) of 5f= 5+3= 8

(n+l) of 6p= 6+1= 7

(n+l) of 5p= 5+1= 6

(n+l) of 4d= 4+2= 6

Therefore, the decreasing order of energy of the given orbitals is 5f> 6p> 5p> 4d.