Consider the hydrocarbon below. 2 carbons are double-bonded to each other; the pair are single bonded to H above left, above right, below right, and below left. What is the name of this hydrocarbon?

Ethene.

Explanation:

To know the name of the compound given above, we must:

1. Determine the number of carbon present in the compound.

2. Determine whether a single, double or triple is present in the compound.

3. Combine the above to get the name.

Now, let us name compound given above. This is illustrated below:

1. The compound contains two (2) carbon atom.

2. The compound contains a double bond. Therefore, the compound is an alkene.

3. An alkene with two carbon atoms is called ethene.

Therefore, the name of the compound given in the question is called ethene.

it's c. elements are placed in rows based on how may valencies electrons have.