[haj1989]

So the previous part of the question asks you to complete the electron configuration for an atom of Sulfur:

Easy enough: 1s2 2s2 2p6 3s2 3p4

It then asks how many full orbitals are in an atom of sulfur. So I know that an orbital holds up to a max of 2 electrons...so I thought the logical conclusion from the above configuration would be sulfur holding 8 full orbitals, but the mark scheme says 7....help! Don't understand that!

Thanks

[EierVonSatan]

Think about how electrons fill into the orbitals, they pair up as a last resort

[haj1989]

(Original post by EierVonSatan)
Think about how electrons fill into the orbitals, they pair up as a last resort

But in 3p4 surely there would be 2 pairs of electrons? I'm clearly to thick to understand this

[EierVonSatan]

(Original post by haj1989)
But in 3p4 surely there would be 2 pairs of electrons? I'm clearly to thick to understand this

No you're not

p subshells have 3 orbitals, yeah? You have 4 electrons to place and you want to avoid pairing them up, because there is a small energy cost in doing so (electrostatic repulsion). So, how many full orbitals are there in a 3p⁴ (ground state) configuration?

[haj1989]

(Original post by EierVonSatan)
No you're not

p subshells have 3 orbitals, yeah? You have 4 electrons to place and you want to avoid pairing them up, because there is a small energy cost in doing so (electrostatic repulsion). So, how many full orbitals are there in a 3p⁴ (ground state) configuration?

Ah I see! Understood! Thanks for the help

[Hillbilly101]

(Original post by haj1989)
So the previous part of the question asks you to complete the electron configuration for an atom of Sulfur:

Easy enough: 1s2 2s2 2p6 3s2 3p4

It then asks how many full orbitals are in an atom of sulfur. So I know that an orbital holds up to a max of 2 electrons...so I thought the logical conclusion from the above configuration would be sulfur holding 8 full orbitals, but the mark scheme says 7....help! Don't understand that!

Thanks

So with orbitals, they pair up, as a last resort. Electrons like to be on their own. So 1S2 is 1 orbital, 2S2 is another, 2P6 is 3 pairs (so far 5 full orbitals), 3S2 is another (6 orbitals in total). Then we come onto 3P4. The P orbitals can hold a maximum of 6 electrons, so three pairs. So the first three electrons occupy the 3 orbitals on their own, but we have an electron left over, so that pairs up with one of the electrons, making up the 7 full orbitals. The atom has 2 orbitals with only 1 electron in. This is because this is the lowest energy configuration.