When writing the electronic formula, did it require eight electrons around the element in the molecular compound? (Except H) I seem to have heard this sentence before, I don't know why

When writing the electronic formula, did it require eight electrons around the element in the molecular compound? (Except for H) This sentence seemed to have been heard before. He did not know if he had heard it wrong or something. solve

Answer 1

When writing the electronic formula, one usually only needed to give the electronic structure around the atom for the elements in the molecular compound, not the electronic formula of the entire atom. This was because the elements in a molecular compound shared their electron pairs to achieve the pairing of their valences, so each element only needed to give part of the electronic structure around the shared electron pair.

For example, for a molecular compound like carbon dioxide, we can just write down the electronic structure around the carbon atom:

```
C + O -- C + O --
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
```

It could be seen that the carbon atom only gave the partial electronic structure around its four valency electron pairs, but there was no need to give the electronic formula of the entire carbon atom.

Of course, in some special cases, such as the carbon chain or the ring formed between carbon atoms in organic compounds, the entire carbon chain or ring needed to be described in electronic form. However, in general, for the elements in a molecular compound, one only needed to give the electronic structure around the atom.