How does an element differ from a compound

Frictional forces acting on an object are often converted into energy, which causes the temperature of the object to rise slightly.

What are the first three quantum numbers for the electrons located in subshell 2s?

Which process does not require the presence of a physical substance in order to transfer heat? air in the atmosphere is heated by the ground. this warm air then rises, and cooler air falls. this is an example of what type of process? how is conduction different from radiation?