Final answer:
Silver, copper, and gold are three elements that are excellent conductors of both heat and electricity due to their high density of free electrons.
Step-by-step explanation:
Three elements that are good conductors of both heat and electricity include silver, copper, and gold. These metals are known to have a high density of free electrons that can move easily through the material, which is why they are capable of conducting electricity and heat effectively. Silver is the best conductor among them, followed by copper and gold. However, aluminum is also a notable conductor that is often used in cooking utensils and industry.