Answer: four electrons
Step-by-step 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.