lemon soda vs sodium

lemon soda

noun
  • A fizzy non-alcoholic drink made with soda and lemon. 

sodium

noun
  • Employing sodium. 

  • The chemical element (symbol Na) with an atomic number of 11 and atomic weight of 22.990. It is a soft, waxy, silvery, reactive alkali metal that is never found unbound in nature. 

How often have the words lemon soda and sodium occurred in a corpus of books? (source: Google Ngram Viewer )