A molecule of ethanol has two carbon atoms, six hydrogen atoms, and one oxygen atom. A ball-and-stick model of a molecule of ethanol is made from the following components:

one red ball
two black balls
six white balls
eight sticks

What do the black balls in the model represent?

The black balls in the model represent the carbon atoms in the molecule of ethanol.

The black balls in the model represent the carbon atoms in the ethanol molecule.

The black balls in the model of ethanol represent the carbon atoms in the molecule. Carbon atoms are often depicted as black balls in ball-and-stick models. In this case, since ethanol has two carbon atoms, there are two black balls used to represent them.