Question : 4d, 5p, 5f and 6p orbitals are arranged in the order of decreasing energy. The correct option is

**(1) 5f > 6p > 5p > 4d**

(2) 6p > 5f > 5p > 4d

(3) 6p > 5f > 4d > 5p

(4) 5f > 6p > 4d > 5p

answer : from all above options the correct answer is “

**(1) 5f > 6p > 5p > 4d**“explanation of correct answer : Smaller the value of (n + 1) for a particular subshell , smaller will be its energy. if the value of n+1 is small in quantity than it’s energy also will be small.

If for two subshells, the (n + 1) value is the same then the subshell having higher value of n will have higher energy it means if the n+1 is higher than the energy of it’s subshell also will be higher , let’s calculate the n+1 value and on the based of n+1 value the energy will be decided.

For 4d : (n + 1) = 4 + 2 = 6 ; For 5p : (n + 1) = 5 + 1 = 6 ; For 6p : (n+1)= 6+1 = 7 ; For 5f : (n + 1) = 5 + 3 = 8 Hence, the correct order of decreasing energy will be 5f > 6p > 5p > 4d.

that is why the correct answer is : – option (1)