The biggest source of metals is earth’s crust. Some other soluble salts of the metals are found in sea-water. Mostly in nature metals occur in combined state but sometimes free. The metals those are least reactive and those have little affinity for moisture, oxygen and other chemical reagents occur in metallic or free or native state example, in uncombined state. Generally the metals ... https://www.expertsmind.com/chemistry/extraction-of-metals-homework-assignment-help.aspx