Question

Identify the orbitals which are filled in the 6th period? 1)6s 4f 5d 6p 2) 6s 6p 5f 6d 3) 6s 6p 6d 6f 4) 6s 5f 6p 6d

Answer 1

Identify the orbitals which are filled in the 6th period ?

1. 6s, 4f , 5d , 6p
2. 6s , 6p, 5f , 6d
3. 6s , 6p , 6d , 6f
4. 6s , 5f , 6p , 6d

solution : According to Aufbau's principle,

1. electrons are filled in a orbital in order of increasing value of (n + l) value
2. For subshells with same value of (n + l) value, electrons are filled first to the subshell with lower n ( principal quantum number)

now let's see n and l value of s , p , d and f

for 6s

l = 0, n = 6 so, (n + l) = 6

for 4f

l = 3, n = 4 so, (n + l) = 4 + 3 = 7

for 5d

l = 2 , n = 5 , (n + l) = 5 + 2 = 7

for 6p

l = 1 , n = 6 , (n + l) = 6 + 1 = 7

applying Aufbau's principle, order will be 6s, 4f, 5d, 6p

Therefore the correct option is (1) 6s, 4f , 5d , 6p