| The discovery of new elements (pre-16) |
|
Humphry Davy – electrolysis |
|
|
Humphry Davy took advantage of new technology to discover six elements. He used the then-newly invented voltaic pile (we would call it a battery), to pass electricity through molten salts of alkali metals. This produced highly reactive metals at the negative electrode. He obtained sodium and potassium, then magnesium, calcium, barium and strontium. QuestionsQ 1. (a) Why could Davy not isolate, say, sodium from sodium oxide by reducing the oxide with carbon as Berzelius had done with silicon, cerium, thorium and selenium? (b) Why did Davy electrolyse molten salts rather than solids? (c) Why did Davy electrolyse molten salts rather than solutions of salts in water? |
|
