I hate Chemistry?

Question

does anybody know what kind of structures these are likely to have and the nature of the bonds in the oxides that are formed when they react with excess oxygen?

I'm stuck on Potassium,
Selenium,
Nitrogen and
Calcium

Thanks

Answer 1

Potassium (K) Metallic lattice in a 'sea of electrons'.Ionic bonding to form K2O.
Selenium (Se) Non metallic - individual atoms. Covalent bonding forming SeO2
Nitrogen (N) diatomic molecule N2. Covalent bonding to form NO2 or NO or N2O.
Calcium (Ca) Metallic lattice in a 'sea of electrons'. Ionic bonding forming CaO.

Answer 2

Potassium oxide: K2O is formed with a limited amount of oxygen, the superoxide KO2 is formed by burning potassium in pure oxygen. The question probably asks for the superoxide form as in K2O formation the potassium is in excess.

Selenium dioxide is a covalent compound: [O-Se-O-Se]n
II II
O O
Selenium dioxide is a crystalline with a long chain structure.

There are a number of different nitrogen oxides, I think nitrogen dioxide NO2 is the most complete combustion. Nitrogen forms NO when burnt but this reacts with oxygen to become NO2. NO2 is a free radical (has one unpaired electron). It is gaseous and is O=N-O, the double bond is usually shared between the two nitrogens but I can't make the computer draw it.

The only calcium oxide I know of is CaO, it has a crystal structure.

(Ahh stupid program won't let me line up the double bond oxygens correctly they are each supposed to be attached to the selenium)

Answer 3

K2O (ionic)
SeO (Colvent at a GUESS)
N2O3 (but could anything due to numberous of amoult of nitrorous oxides) (colvent)
CaO (ionic) linear