The chemical properties of an element are largely determined by its
a. number of energy levels.
b. period number.
c. number of protons.
d. number of valence electrons.

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?