1.- The energy of a wave will increase the frequency due to the increase in the speed of the wave.
2.- The wavelength will increase if the energy of the wave increases, due to the area that is expand.
3.- A wave with a higher frequency will have faster speed to move.
Explanation:
Wavelength of a wave is due to the speed and the energy that the wavelength carry, so if the energy increases, this quantity of energy need to distribute or in the wavelength or in the frequency, to conduct the wave with a bigger amount of energy.
Frequency is related to the energy carried by the wave, the higher the energy the faster it oscilates and the higher the frequency. The wavelenght is the distance between two consecutive valleys of a wave. It's inversely proportional to the frequency, therefore if the frequency increases with the energy, the wavelength decreases.
Aluminum foil does contain billions of atoms, but we write them just as Al because aluminum does not exist in single atom forms in normal circumstances but as billions in metallic bonds.