Answer
C : $1s^22s^22p^2$
P : $1s^22s^22p^63s^23p^3$
Ar : $1s^22s^22p^63s^23p^6$
Na : $1s^22s^22p^63s^1$
Work Step by Step
The electronic configurations are:
C : $1s^22s^22p^2$ (6 electrons)
P : $1s^22s^22p^63s^23p^3$ (15 electrons)
Ar : $1s^22s^22p^63s^23p^6$ (18 electrons)
Na : $1s^22s^22p^63s^1$ (11 electrons)
