If the Aufbau principle had not been followed, Ca (Z = 20) would have been placed in the:
a) s-block
b) p-block
c) d-block
d) f-block
The correct answer is option 'C'. Can you explain this answer?

Chemistry Question

Aakash Pandey
May 31, 2018
Electronic configuration of Ca is 1s2 2s2 2p6 3s2 3p6 4s2. 
Filling of 3d orbital starts after the filling of 4s orbitals. If the aufbau principle had not been followed, the filling of 3d orbital would have been prior to filling of 4s orbital and the electronic configuration of Ca would have been   1s2 2s2 2p6 3s2 3p6 3d2 and it belongs to d block.

Vishal Thakur
Jun 15, 2018
Hey buddy,As you know that aufbau principle states that filling of orbitals takes place in increasing order of energy means orbitals having less energy are filled first. Now, in calcium we put the last two electrons in 4s orbital because 4s orbital has less energy than 3d orbital. Now,If there was no aufbau principle then there was no energy criteria for filling up of electrons and electrons are filled according to their number like 1s,2s,2p,3s,3p,3d,4s....and so on.And according to this order the last electron of calcium will enter the d-orbital and hence it will be placed in the d-orbital.

Ashwant Tuty
Feb 03, 2019
Answer will be s-block.Becouse their outer most electrons enter in s-subshell.

Shivani Palwar
Oct 03, 2019
Ca+2 electronic configuration is 1s2 2s2 2p6 3s2 3p6 4s2. but if we not obey the aufbau rule then the last electron was not pairing in 4s orbital &move to next energy orbital
3d. so the answer is d orbital

Option c i.e d block is right bcz according to its electronic configuration its last electron goes to 4s subshell but when aufbau principle is violated its last electron goes to 3d subshell bcz the capacity of 3p is filled and 3d is prior to that of 4s avoiding its energywhich is greater than the former. so d block is right.

Prashant Kumar
Sep 07, 2019
Since aufbau principle states that electrons are progressively filled in order of their increasing energies so 4s is filled first having lower energy than 3d but if the rule is violated 3d would be filled first and the config would be1s2,2s2,2p6,3s2,3p6,3d2.....

if it is helpful plz like it and comment on the way answer is told or corrections required...

Samruddhi Gavali
Oct 13, 2019
S block outer most electron in s shell

Sha Sha
Sep 19, 2019
By not considering aufbau principle the electron should enter in 3d orbital before 4s so its configuration will be 1s(2) 2s(2) 2p(6) 3s(2) 3d(2) I.e. last electron is entering in d orbital so it would have been placed in d block.

This discussion on If the Aufbau principle had not been followed, Ca (Z = 20) would have been placed in the:a) s-blockb) p-blockc) d-blockd) f-blockThe correct answer is option 'C'. Can you explain this answer? is done on EduRev Study Group by Chemistry Students. The Questions and Answers of If the Aufbau principle had not been followed, Ca (Z = 20) would have been placed in the:a) s-blockb) p-blockc) d-blockd) f-blockThe correct answer is option 'C'. Can you explain this answer? are solved by group of students and teacher of Chemistry, which is also the largest student community of Chemistry. If the answer is not available please wait for a while and a community member will probably answer this soon. You can study other questions, MCQs, videos and tests for Chemistry on EduRev and even discuss your questions like If the Aufbau principle had not been followed, Ca (Z = 20) would have been placed in the:a) s-blockb) p-blockc) d-blockd) f-blockThe correct answer is option 'C'. Can you explain this answer? over here on EduRev! Apart from being the largest Chemistry community, EduRev has the largest solved Question bank for Chemistry.
This discussion on If the Aufbau principle had not been followed, Ca (Z = 20) would have been placed in the:a) s-blockb) p-blockc) d-blockd) f-blockThe correct answer is option 'C'. Can you explain this answer? is done on EduRev Study Group by Chemistry Students. The Questions and Answers of If the Aufbau principle had not been followed, Ca (Z = 20) would have been placed in the:a) s-blockb) p-blockc) d-blockd) f-blockThe correct answer is option 'C'. Can you explain this answer? are solved by group of students and teacher of Chemistry, which is also the largest student community of Chemistry. If the answer is not available please wait for a while and a community member will probably answer this soon. You can study other questions, MCQs, videos and tests for Chemistry on EduRev and even discuss your questions like If the Aufbau principle had not been followed, Ca (Z = 20) would have been placed in the:a) s-blockb) p-blockc) d-blockd) f-blockThe correct answer is option 'C'. Can you explain this answer? over here on EduRev! Apart from being the largest Chemistry community, EduRev has the largest solved Question bank for Chemistry.