A molecular structure in which all formal charges are zero is preferable to one in which some formal charges are not zero. A few guidelines involving formal charge can be helpful in deciding which of the possible structures is most likely for a particular molecule or ion: In many cases, following the steps for writing Lewis structures may lead to more than one possible molecular structure-different multiple bond and lone-pair electron placements or different arrangements of atoms, for instance. The arrangement of atoms in a molecule or ion is called its molecular structure. N: 0 all three Cl atoms: 0 Using Formal Charge to Predict Molecular Structure Thus, we calculate formal charge as follows: Another way of saying this is that formal charge results when we take the number of valence electrons of a neutral atom, subtract the nonbonding electrons, and then subtract the number of bonds connected to that atom in the Lewis structure. The formal charge of an atom in a molecule is the hypothetical charge the atom would have if we could redistribute the electrons in the bonds evenly between the atoms. We can use the concept of formal charges to help us predict the most appropriate Lewis structure when more than one is reasonable. As we have seen, however, in some cases, there is seemingly more than one valid structure for a molecule. In the previous section, we discussed how to write Lewis structures for molecules and polyatomic ions.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |