Fill in the blank. a change occured when a metal changed color because it reacted with another substance.

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?

Elements in group 2 are all called alkaline earth metals. what is most similar about the alkaline earth metals?

If a particle has z = 25 and 23 electrons, what is its charge?