A LESSON IX CHEMISTRY 



usually the initial of its name, as C for carbon and P for 

 phosphorus. When the initial is duplicated in the list of 

 symbols, one more distinguishing letter may be added, as 

 Ca for calcium and Pt for platinum. Occasionally an element 

 may be given the initial of an older name, as in the case of K 

 for potassium, where the initial stands for kalium. Iron has 

 the symbol Fe, derived from ferntm. The student familiar 

 with the names of the elements readily recognizes the kinds 

 of atoms that form a given compound when its formula is 

 read. When more than one atom of a kind enters into the 

 combination, the number is written below the line and im- 

 mediately following the symbol. Thus the formula CO 2 , 

 representing a molecule of carbon dioxide, is seen to consist of 

 one atom of carbon united with two atoms of oxygen. The 

 molecule of water is written H 2 O. In this two atoms of 



TABLE OF THE MORE COMMON CHEMICAL ELEMENTS 



