How many electrons are involved when two atoms in a molecule are connected by a "double bond"? write the lewis structure of a molecule containing a double bond?

Answer: four electrons

Explanation:

Each bond is formed by a pair of electrons. So, two bond involve two pairs of electrons, which is 2 * 2 = 4 electrons.

The Lewis structure for a doble bond is:

X : : X

where the dots represent the electrons, and one dot beside other dot is a pair of electrons formin a bond.

So, there you have two pair of electrons representing two bonds or one double bond.