Book Online Demo
Check Your IQ
Try Test

Courses

Dropper NEET CourseDropper JEE CourseClass - 12 NEET CourseClass - 12 JEE CourseClass - 11 NEET CourseClass - 11 JEE CourseClass - 10 Foundation NEET CourseClass - 10 Foundation JEE CourseClass - 10 CBSE CourseClass - 9 Foundation NEET CourseClass - 9 Foundation JEE CourseClass -9 CBSE CourseClass - 8 CBSE CourseClass - 7 CBSE CourseClass - 6 CBSE Course
Offline Centres

Q.

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

see full answer

Start JEE / NEET / Foundation preparation at rupees 99/day !!

21% of IItians & 23% of AIIMS delhi doctors are from Sri Chaitanya institute !!
An Intiative by Sri Chaitanya

a

Both ‘A’ and ‘R’ are true and ‘R’ is the correct explanation of ‘A’.

b

‘A’ is true but ‘R’ is false

c

Both 'A' and 'R' are false

d

Both ‘A’ and ‘R’ are true and ‘R’ is not the correct explanation of ‘A’

answer is A.

(Unlock A.I Detailed Solution for FREE)

Ready to Test Your Skills?

Check your Performance Today with our Free Mock Test used by Toppers!

Take Free Test

Detailed Solution

  • According to Aufbau's principle, the unfilled shell with lowest (n + l) value will be filled first. so 4s orbital is filled first than 3d orbital.  
  • For 4s - orbital, (n + l) = 4 + 0 = 4 
  •  For 3d - orbital, (n + l) = 3+2 = 5
Watch 3-min video & get full concept clarity
Related Blogs
Get ₹ 1 crore* worth scholarship for JEE / NEET / Foundation
Result Producing online coaching for JEE/NEET of south India
Largest All India Test Series for JEE/NEET
Best Books for IIT JEE
Best Books for NEET
How to Join IIT after 10th
score_test_img

Get Expert Academic Guidance – Connect with a Counselor Today!

Related Blogs
Get ₹ 1 crore* worth scholarship for JEE / NEET / Foundation
Result Producing online coaching for JEE/NEET of south India
Largest All India Test Series for JEE/NEET
Best Books for IIT JEE
Best Books for NEET
How to Join IIT after 10th
whats app icon
(A) : The 19th electron in potassium atom enters into the 4s - orbital and not into the 3d- orbital.(R) : (n + l) rule is followed for determining the orbitals of the lowest energy state.