Difference between cuprous and cupric ferrous and ferric
If an element exhibits two different positive valencies, then we use suffix ‘ous’ for the lower valency and ‘ic’ for the valency.
Iron exhibits two variable valencies Fe+2 and Fe+3
Fe+2 is called ferrous ion and Fe+3 is called ferric ion.
Copper exhibits two variable valencies Cu+1 and Cu+2
Cu+1 is called cuprous ion and Cu+2 is called cupric ion.