Metal	Occurrence
X	Always available in the combined sate
Y	Always available in both combined and native sate
Z	Always available in native state only

 

X, Y and Z can be

Only two metals, gold and platinum are found principlally in their native state. So Z may be Pt or Au.

$\to$  Silver is found in nature both in native and combined state. Silver is less reactive than other metals native silver occurs and elongated dendritic coatings or irregular masses. It may occur alloyed with gold as electrum.

$\to$  Highly reactive metals alloys available in combined state i.e.

Ex: K, Na, Ca, Mg, Al, Zn, Fe, Pb, Etc.