The electronic configuration of the element of atomic number 27 is .
A
$$1s^2,2s^22p^6,3s^23p^6,4s(\uparrow\downarrow)4p(\uparrow\downarrow)(\uparrow\downarrow)(\uparrow\downarrow)5s(\uparrow)$$
B
$$1s^2,2s^22p^6,3s^23p^6,3d(\uparrow\downarrow)(\uparrow\downarrow)(\uparrow\downarrow)(\uparrow\downarrow)4s(\uparrow)$$
C
$$1s^2,2s^22p^6,3s^23p^6,3d(\uparrow\downarrow)(\uparrow\downarrow)(\uparrow\downarrow),4s(\uparrow\downarrow)4p(\uparrow)$$
D
$$1s^2,2s^22p^6,3s^23p^6,3d(\uparrow\downarrow)(\uparrow\downarrow)(\uparrow)(\uparrow)(\uparrow),4s(\uparrow\downarrow)$$
Correct option is A. $$1s^2,2s^22p^6,3s^23p^6,4s(\uparrow\downarrow)4p(\uparrow\downarrow)(\uparrow\downarrow)(\uparrow\downarrow)5s(\uparrow)$$
