Which of the following series of transitions in the spectrum of hydrogen atom fall in visible region?
Balmer series
Paschen series
Brackett series
Lyman series
Non - directional orbital is :
4p
4d
4f
3s
D.
3s
Non - directional orbital is : 3s because s - sub - shell has only one orbital and it is spherical .Hence , s - orbitals are non - directional .
Assertion (A) : Atoms with completely filled and half-filled sub-shells are stable.
Reason (R): Completely filled and half-filled sub-shells have symmetrical distribution of electrons and have maximum exchange energy.
The correct answer is
(A) and (R) are correct, (R) is the correct explanation of (A)
(A) and (R) are correct, (R) is not the correct explanation of (A)
(A) is correct, but (R)is not correct
(A) is not correct, but (R) is correct