how can we identify the oxidation states from an element's electronic configuration ? explain with example.
Only a general idea can be predicted using the electronic configuration.
Halogens have only one electron less than the next noble gas.
Therefore, they can get the noble gas configuration either by gaining one electron to form uni negative ion, X-, or by sharing electrons with other atoms.
Thus, they show an oxidation of state of -1 or + 1. Since fluorine is the most electronegative element, it always shows an oxidation state of -1. It does not show any positive oxidation state.