1. The problem statement, all variables and given/known data Hello PF! I had a lab practice a while ago of using flames to identify elements by its color. It had the first three alkali metals, calcium, magnesium and barium. We didn't use beryllium or strontium for whatever reason. I don't know why we didn't use them, and that's why I come here. They are not super toxic, so that's not it. Is it because their salts are too expensive or difficult to obtain, or anything else? Does anyone know something?