IIT JEE , AIEEE Forum - Chemistry , Inorganic Chemistry - why is electron promoted to 3d subshell and not 4s from 3p subshell?

b_friendz23

why is electron promoted to 3d subshell and not 4s from 3p subshell?

kashyap6552

ur question is wrong...4s is filled up first then 3d....acc to aufbau principle....as 4s is having less energy then 3d....so it get filled up first den 3d.dere is 1 more formula 4 calculating d energies
...just put d value of 4s subshell---->n(principle quantum no.)=4+l(magnetic quantum no.)=0.....wich sum to 4.....now calculate for 3d subshell------->n=3+L=2....which sums to 5
since the 4s subshell has lower value of (n+l)therefore it possess d lower energy and filled first.....rate f understood...thanks

kashyap6552

its d simple question....go through pradeep 4 more clarity...rate f satisfy....thanks

dream_iit

yes according to n+l rule and aufbau principle....4s is filled first

kundan_leo

yaar its a simple concept in which often people get confused.....

just remember that electrons get filled up first in a lower energy level and then in a higher one...

irrespective of the numerical order.....

energy level can be determined by n+l value.......

just remeber it as a shelf.....

dalte wakt we see that every lower layer is filled before proceeding to the next level....

par nikalte wakt we just come down numericallly...the ouetr layer first and so on.......

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