Question #e98c0

1 Answer
Nov 9, 2017

To understand this you need to appreciate that the order in which metals were found relates to their reactivity.


Gold, silver and copper do not readily form oxides at all and so were known since ancient times in their elemental form (if you’re lucky, you can just dig a lump of pure metal out of the ground.)

More reactive metals (I’m thinking of iron, zinc etc. that lie below carbon) can be extracted from their ores (rocks containing compounds of the element) by smelting (heating in a furnace) with carbon. The carbon displaces the metal and reacts with the non-metal group. Others were discovered through their reactions with acids, steam etc.

The most reactive metals (aluminium, lithium, sodium etc) cannot be purified in this way so rely on electrochemical processes (electrolysis). This process was unknown until very late in the 18th
century. It relies on very large direct currents and carefully designed processes, neither of which were readily available until the start of the 19th century.