I have an old periodic table and I marked five metals from groups 1A and 2A with dots to indicate something about them. Only all this time later I can't figure out what exactly it was. I've been trying to figure it out for ages.
The elements are: Li, Na, K, Ca, Ba.
Doesn't anyone know any properties that just those elements, or maybe even just primarily those five, share that I could have been marking them for?