Which picture shows the correct flow of electrical current

The bond energy for the van der waals bond between two helium atoms is 7.9×10−4ev. assuming that the average kinetic energy of a helium atom is (3/2)kbt, at what temperature is the average kinetic energy equal to the bond energy between two helium atoms

The identities of substances are the same before and after which type of change

Who determined the nature of chemical bonds?