Indicate the number of unpaired electrons in (1) P,
(2) Si,
(3) Cr,
(4) Fe and (5) Kr.

Explanation

(1) `""_(15)P=1s^(2)2s^(2)2p^(6)3s^(2)3p_(x)^(1)3p_(y)^(1)3p_(z)^(1),` number of unpaired electrons.=3.
(2) `""_(14)Si=1s^(2)2s^(2)2p^(6)3s^(2)3p_(x)^(1)3p_(y)^(1),` number of unpaired electrons=2.
(3). `""_(24)Cr=1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(5)4s^(1)`, number of anpaired electrons=6 (5 in d-subshell & 1 in s-subshell)
(4) `""_(26)Fe=1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(6)4s^(2)`, number of unpaired electrons in d-subshell=4.
(5) `""_(36)Kr=1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(10)4s^(2)4p^(6)`, number of unpaired electrons=0.