The three-letter words below have something in common that has nothing to do with their meanings. Can you determine what it is?

BAR
CAR
COB
COP
LIT
NIT
POT
SOD

HINTS:
1. The answer words can all be found in the same place.
2. That place is often on a classroom wall.

Answers:

The clue words are the first three letters of eight elements:

BARIUM
CARBON
COBALT
COPPER
LITHIUM
NITROGEN
POTASSIUM
SODIUM