3.Supposetherulesforassigningquantumnumberswereasfollows:
n=1,2,3,…
l=0,1,2,…,n
m=0,1,2,…,l+1
s=+or-Statethevaluesofl,m,sfortheelectronswhenn=1andn=2.Givetheelectronconfigurationforanatomwithtwelveelectrons.