SO3 polyatomic ion transfer electron?

Question

I was trying to draw a electronic diagram of SO3. S, which has bonded with 3 O, got 9 electrons in its outermost shell. So, would it transfer a electron to the O which need it? Also, should I fill the atom with a higher ability to gain electrons first? Like N and O, they are in the same period, but O have more protons, so I need to fill O to 8 electrons first and the N gain 1 from other particle and form a polyatomic ion with a charge of 1-. Am I right?

Answer 1

Do you want SO3 or SO3 2-? (Q. mentions an ion)

Either way, in SO3 there are two ways of doing it. You can expand the octet round S, and double bond to all O atoms to give O its octet. Or you can transfer an electron from S to each of two O atoms, single bond to them, and double bond to the third. (Of course, all O become equal by resonance). Either way, you should end up with no lone pairs on S.

SO3 2- is rather similar but you have to find homes for 2 more electrons.

I suggest doing NO3- (sort of isoelectronic, but without the possibility of expanding te central atom octet) as a warmup problem.

Over to you. Enjoy!