At GCSE, teachers are always at their wits’ end desperately trying their best to make their subjects one which students will enjoy and perhaps lead on to A-level and beyond, safe in the knowledge that they have inspired a child – which is ultimately one of the greatest joys in teaching. My chemistry teacher was one such teacher who always introduced experiments into her lessons whenever possible. One particular experiment which all my classmates loved was the reaction of alkaline earth metals with water.
The ‘Oos’ and ‘Ahs’ that escaped my classmates’ mouths are still fresh in my memory as my teacher dropped that seemingly boring small silver chunk of soft metal into the water bath below. The bang, smoke and fizzing that ensued as the metal skimmed across the surface of the water with the elegance of a professional ice skater brought everyone to ask the same question: How did you do that?
The question isn’t really the most accurate but still allowed the teacher to vet our instinctive eagerness to ask: ‘how does that happen’? The reaction occurring is the formation of the alkaline lithium hydroxide and hydrogen. Lithium hydroxide is alkaline and so will cause the water to be a ‘basic’ solution. The hydrogen gas can be collected in a test tube and, if released next to a flame, it will give a characteristic squeaky pop as it is ignited. If you’re eager for a visual representation of this experiment watch a video on YouTube!
Lithium is so reactive that it will readily react with air to form a layer of lithium oxide, causing the metal to have a dull grey tarnished look. If you cut into it, the true shiny metallic colour is revealed. In order to slow this reaction down, lithium is stored in oil.
In our everyday lives, we take advantage of lithium. Lithium ion rechargeable batteries supply power to practically every electrical appliance we use and sometimes can’t live without, like our mobiles phones and laptops. They work by transporting Li+ ions from the positive electrode to the negative electrode when discharging and back again when being charged. Another common use of lithium is in flares and pyrotechnics because of its characteristic rose-red coloured flame.
To end on yet another fact; there’s only one lithium joke in the world. Honestly. Would I Li to you?