What do the following words have in common that has nothing to do with their meanings?

CAN

CAP

NAP

BONE 

CLIP

KINE 

HINT:

Look at the letters, not the words.

Answer:

 

By changing some of the capital letters to lower case, each word is entirely composed of symbols of chemical elements: 

 

CaN

CaP

NaP

BONe

CLiP

KINe