7. Tungsten is a conductor, the rest listed are insulators.
8. Thermal Energy
I believe this is a double replacement. As you can see none of the chemical symbols are missing, there just "replaced".
Answer: Friction is the resistance to motion of one object moving relative to another. It is not a fundamental force, like gravity or electromagnetism. Instead, scientists believe it is the result of the electromagnetic attraction between charged particles in two touching surfaces.
Explanation:
Lanthanide belongs to period 6, and actinides belongs to period 7
