I can not figure out how to predict the structures and central hybridization of these atoms.?

Question

For the ions: N3 - , CO3 (2-), NO3 -, and BF4 -
i need to find out how to find the structures and central atom hybridizations. I am not focusing well right now as I am trying to recover from a virus and all of this is looking Greek to me right now....HELP!

Answer 1

N(3-):
Nitrogen atom is in 5A group thus has 5 valence electrons. N(3-) has 8 valence electrons, thus fill all its 2s and 2p orbitals. Since it is a mono-atomic ion, "hybridization" does not make any sense.

CO3(2-):
Carbon atom is in 4A group thus has 4 valence electrons. CO3(2-) has 6 valence electrons. All its valence electrons take part in bonding to 3 oxygen atoms. It involves 3 resonance structures to fulfill octet rule. You will convince yourself if you draw out the Electron-Dot Structure of the three resonance structures. Thus it adopts a trigonal planar arrangement, and it went a sp2 hybridization.

NO3 -
Nitrogen atom is in 5A group thus has 5 valence electrons. NO3(-) has 6 valence electrons. Hence this case is identical to CO3(2-) case in electron-configuration. namely, it adopts a trigonal planar arrangement, and it went a sp2 hybridization.

BF4 -
Boron atom is in 3A group thus has 3 valence electrons. Boron atom in BF4(-) has 4 valence electrons, and it gains 4 more electrons in bonding to 4 fluorine atoms. Thus it went a sp3 hybridization, and adopts a tetrahedron arrangement.

Answer 2

sorry dude, I'm stumped already. Is this college chemistry?