On the Periodic Table, that is. Fun with the alkali metals.

I’ve witnessed a pretty nice Rubidium reaction, when I was cleaning out the oven we used to make an atomic beam. The oven was little more than a pipe with a hole in it, along with a removable plug for refilling/cleaning access, and heater wire wrapped around the outside. A little squirt of water into the tube, and BOOM! Turns out there was a macroscopic bit of unoxidized Rb left inside. Good times.