Assertion: The 19th electron in potassium atom enters into the 4s - orbital and not into the 3d - orbital. Reason: (n + 1) rule is followed for determining the orbitals of the lowest energy state.

Question

Assertion: The 19th electron in potassium atom enters into the 4s - orbital and not into the 3d - orbital. Reason: (n + 1) rule is followed for determining the orbitals of the lowest energy state. (A) It both Assertion and Reason are true and the Reason is a correct explanation of the Assertion (B) If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion (C) If Assertion is true but the Reason is false (D) If both Assertion and Reason is false

Tardigrade Admin · Accepted Answer

According to Aufbau principle, the unfilled shell with lowest

(n + l)

value will be filled first. Therefore, 4 s orbital is filled first then

3 d

orbital.

for

4 s -

orbital,

(n + l) = 4 + 0 = 4

for

3 d -

orbital,

(n + l) = 3 + 2 = 5

Q. Assertion: The 19th electron in potassium atom enters into the 4s - orbital and not into the 3d - orbital. Reason: (n+1) rule is followed for determining the orbitals of the lowest energy state.

It both Assertion and Reason are true and the Reason is a correct explanation of the Assertion

If both Assertion and Reason are true but Reason is not a correct explanation of the Assertion

If Assertion is true but the Reason is false

If both Assertion and Reason is false

According to Aufbau principle, the unfilled shell with lowest (n+l) value will be filled first. Therefore, 4 s orbital is filled first then 3d orbital. for 4s− orbital,(n+l)=4+0=4 for 3d− orbital,(n+l)=3+2=5

Q. Assertion: The $1 9^{t h}$ electron in potassium atom enters into the $4 s$ - orbital and not into the $3 d$ - orbital.
Reason: $(n + 1)$ rule is followed for determining the orbitals of the lowest energy state.

According to Aufbau principle, the unfilled shell with lowest $(n + l)$ value will be filled first. Therefore, 4 s orbital is filled first then $3 d$ orbital.

for $4 s -$ orbital, $(n + l) = 4 + 0 = 4$

for $3 d -$ orbital, $(n + l) = 3 + 2 = 5$