<span>Fe(NO3)2
The NO3 part is a poly-atomic ion with total charge -1.
This is because Fe has a +2 charge and two NO3's with a -1 charge will balance out to 0.
Most often we just make the assumption that Oxygen has a -2 oxidation number because it is very electro-negative.
So to find N, we just need an oxidation number that balances out with 3(-2) to get -1 (the total charge of the ion)</span>
Answer:
Looks like they're all right
I can't see the picture, but in general, I believe it is in dropping from the first energy level above the ground state, to the ground state.
Ionic bonds is formed between metal and nonmetal with opposite charges. Metal have (+) charge and nonmetals often have (-) charge.
Choice (a) is wrong because both charges are the same.
Choice (c) is wrong b/c same changes.
Si and O do not have charges for now. (d) is wrong.
Choice (b) is correct. Opposite charges and the ionic compound is BaCl2