Energy is transferred between two objects/partides when they code with each other. Based on this fact and the video describe how a thermometer works at the microscopic level partide ating to a macroscopic change ouderpanding contracting inside the thermometer

conduction is the transfer of thermal energy (heat in transfer) due to collisions between the molecules in the object. collisions between adjacent atoms and molecules transfer kinetic energy from the warmer to the cooler object. the objects must be in physical contact.

answer:

technetium is the most reactive. this is followed by silver. the least reactive out of these three elements is strontium.