Question

Why copper and silver exit in native or free state as well as in combined state?

Answer 1

i think a native metal is any metal that is found in its metallic form. either pure or as in alloy in nature..
so as silver and copper are metals so this could be a reason for this

Answer 2

All the different behaviours of copper and silver are due to their electronic distribution structure in the orbitals.

Ag = 47 : 1s2  2s2  2p6 3s2 3p6  3d10  4s2 4p6  4d10  5s1
cu :   29:  1s2  2s2  2p6  3s2  3p6 3d10  4s1

They exist in nature as the pure metals.   They have just one electron in outermost orbital.  So they can lose that electrons that be will be stable configuration.  The ability to show different oxidation states and valencies comes from the properties of  s,p,d  orbitals in the lower shell.  (the hybridized orbitals).

copper is more reactive than Ag.