What element has the symbol 'Ru'?

The story behind the answer

Ru stands for Ruthenium, a platinum‑group metal (atomic number 44). The other options don’t match the symbol: Rubidium is Rb, Radium is Ra, and Ruthenium chloride is a compound (RuCl3), not an element.

Discovered in 1844 by Karl Ernst Claus, Ruthenium was named after “Ruthenia,” a Latin term for regions of Eastern Europe, including Russia—handy for remembering Ru. It’s used to harden platinum and palladium, in electrical contacts and resistors, and as a catalyst. Memory tip: “RU = RUthenium” and “RUthenia/RUssia” both point to Ru. If you see a compound like “Ruthenium chloride,” remember element symbols refer to pure elements, not their compounds.