[niks]

:shock: :?: How can elements have variable valency? :?: :shock:

:!: An example is of iron. In this forum only, it is given that it can have max. oxidation no. "3" as in Fe2O3. But how can it be possible as its electronic config. is Fe(2,8,14,2) :?: As per my knowledge, substances react to get noble gas config :!: :!: :!: