Where did rubidium get its chemical symbol?

Answer 1

Sometimes the symbol comes from two consecutive letters in the element name, as with Calcium (Ca), sometimes two non-consectutive letters, as with Chlorine (Cl), or Rubidium. Sometimes the symbol comes from the element's Latin name, like Lead (Pb). Also, two uppercase letters are NEVER used in an element symbol, so Rubidium's real symbol is Rb, not RB.

Answer 2

The lating word "rubidius" means dark red and rubidium has red spectroscopic lines

Answer 3

In synthesis, it's a scribal abbreviation like mr, mrs, jr, sr etc.