Metals, Reactivity and King Canute

I crossed out Li and Sn because they didn't fit the mnemonic
I crossed out Li and Sn because they didn't fit in the mnemonic, or memory aid.

Some metals are very boring and unreactive meaning they don’t easily take part in chemical reactions, if at all. Gold and platinum are like this. They don’t form oxides by reacting with oxygen in the air, even if heated strongly, and they don’t react with water either.  Just as well, really – what’d be the point of a ring that fizzed away to nothing in a puff of hydrogen every time it rained?

Some metals are very reactive. They easily – even enthusiastically take part in chemical reactions to make new substances.


mag_burning1Magnesium from Group 2 is like this. If it is heated in a Bunsen burner, it almost immediately ignites and burns with a brilliant white flame, forming basic magnesium oxide, a white powder.  Get your sunglasses on – this is bright!

Some people talk about acids as proton or hydrogen ion donors. Not quite true – a pickpocket doesn’t ask before he steals your wallet, and you don’t give it to him – he just takes it from you. Metals above HYDROGEN in the reactivity series steal the negative ions attached to hydrogen from acids in solution, making a metal salt and hydrogen gas. I’ve put hydrogen in the right place for you, between lead and copper.

Group 1 metals, having only one electron in the outermost shell are highly reactive. Francium is the most reactive – it’s incredibly rare and desperately expensive and its electron is a very long way from the nucleus, so it loses it easily. You won’t see Fr in a reactivity series, however – at least, not this one.

Now for King Canute. This is a ‘nearly mnemonic’ to help you to remember the order of reactivity of some common metals. Almost a thousand years ago, Canute was ‘king of all England, and of Denmark, of the Norwegians, and part of the Swedes’.  Canute had learned that his flattering courtiers claimed he was “so great, he could command the tides of the sea to go back”. Now Canute was not only a religious man, but also a clever politician. He knew his limitations – even if his courtiers did not – so he had his throne carried to the seashore and sat on it as the tide came in, commanding the waves to advance no further. When they didn’t and he got his feet wet, he had made his point that, though the deeds of kings might appear ‘great’ in the minds of men, they were as nothing in the face of God’s power. Nice.

Here’s the mnemonic using symbols for the metals… H is in yellow so everything above it is a thief!

King Canute Never Managed, Although Zealous For Publicity, He Couldn’t Haggle Against Authority.

OK, calcium and sodium (the ‘a’ is missing from Na) are the wrong way round, also the ‘n’ and ‘e’ is missing from zinc and iron, but it’s nearly there – and it helps. I was taught this one forty-five years ago, and I can still remember it…Eugh!

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