Question

Draw the dot structures for the following molecules and arrange them in an approximate
order of stability ranging from, at one extreme, stable and unreactive, through, stable but
reactive, highly reactive, transient and extremely reactive, to unlikely to exist at all.
Provide reasons for making your choices.
CO, NO2, CH2, H3O, BeH3, XeF2, CH4

(Drew the dot structures. Wanted outside collaboration on what we got of a chemical that doesn't exist and the reactivity

Answer 1

Some things to consider:

1. Maximum valency/how many bonds an atom can have. Also consider whether or not an atom has an expanded octet, like Xe or less than a full octet like Be.

2. Resonance structures. If a molecule has more resonance structures it is more stable than a molecule with fewer resonance structures.

3. Unfavorable charge interactions. For example, neutral H3O is unlikely to exist (the oxygen in H2O has a lone pair to donate to H+ to make H3O+, but would not be expected to donate to a neutral H)

Answer 2

If you propose a sequence of molecules I can give you feedback on the order

Answer 3

I said CH2 doesn't exist due to the carbon not meeting the octet rule, H3O has one more extra valence on the oxygen, and BeH3's charges of Be and H doesn't match (not a complete ionic compound)

Answer 4

Would that be right?

Answer 5

CH2 actually can exist, as methylene, with 1 lone pair on the carbon, it’s just not super stable

You are correct that BeH3 wouldn’t exist but it’s more due to the valence of Be (Be can only take two bonds)

Similarly correct with H3O, oxygen typically doesn’t take three bonds so you’re also correct there

Answer 6

CH2 can exist? I heard that it can't exist alone.
i made a chart on the increasing amount of reactivity, and I got this: CH2, CH3, XeF2, NO2, CO. Does that make sense?