Valence electron question

[comed]

Am having difficulties figuring out # of valence electrons in respective subshells- any help will be greatly appreciated! 🙂

# valence electrons of P in PO4^3-
Answer in Kaplan book says: 2 in s subshell, 6 in p, 2 in d (???) for a total of 10 valence electrons
-I know that electrons can enter the d subshell when its in the ionic form, but not sure how that works..

# valence electrons of O in PO4^3-
Answer in Kaplan: 2 in s, 6 in p, 0 in d, for total= 8 valence electrons


Thanks in advance!

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[theonlytycrane]

Draw out the lewis structure and count from there 🙂

 

[aldol16]

-I know that electrons can enter the d subshell when its in the ionic form, but not sure how that works..

Phosphorous has principal quantum number 👎 = 3 so it has a 3d subshell that's not much higher in energy than 3p. Therefore, it can accommodate extra electrons in the d subshell during bonding. Something like oxygen cannot because n = 2 and thus it has no d subshell with low enough energy for electrons to reside in.