Where exactly is the lead in lead crystal, and why is it not visible?
In: 7
A material’s properties don’t just depend on the atoms involved, but how they are bonded together. A material can have completely different appearance and properties than the atoms making it up would have on their own. It’s like how you can build different things out of the same assortment of LEGO bricks.
An example will help this make more sense: Table salt. It’s sodium chloride. That means table salt is completely made up of sodium atoms and chlorine atoms. But wait! Sodium by itself is a [shiny silver-grey metal](https://upload.wikimedia.org/wikipedia/commons/2/27/Na_%28Sodium%29.jpg) that explodes on contact with water. And chlorine by itself is a (very toxic) [greenish-yellow gas](https://groungims.groundwatergovernance.org/is_chlorine_gas_a_molefular_element.png). And yet table salt, sodium chloride, is a [transparent solid](https://www.donkom.ca/wp-content/uploads/2014/05/DKP_2131-1024×713.jpg) that dissolves in water and is safe to eat. How?? It’s because the atoms alone don’t determine the properties – the structure does! In table salt, the [sodium and chlorine are arranged like this](https://media.istockphoto.com/id/1219252433/vector/sodium-chloride-nacl-crystal-structure-over-white.jpg?s=612×612&w=0&k=20&c=PboB_LBjlVjKgg4A-YDblgI5kU9StdBzDyJ2Vi6pQIE=). That’s the key: Sodium chloride contains sodium *atoms*, but does not contain any pure metallic sodium-the-material (which is a bunch of sodium atoms all bonded only *to each other*). And sodium chloride contains chlorine *atoms*, but does not contain any chlorine-gas-the-material (which is chlorine atoms bonded to each other in pairs).
Getting back to your question, you could look at table salt ask “where is the sodium and why is it not visible?” The sodium *atoms* are there, you’re seeing them! But there is no silver sodium *metal* there to be seen, only sodium atoms connected together with chlorine atoms in the pattern that makes table salt, not the pattern that makes sodium metal.
It’s the same with lead crystal. There is no metallic lead-the-solid-grey-metal in lead crystal. The lead atoms are built in throughout the structure of the crystal in such a way that the whole thing is still transparent. The properties of lead that you’re used to (being a dark and solid metal) only arise when you have a bunch of lead atoms only bonded to other lead atoms.
Latest Answers