Consider an iron cube and an aluminum cube. If the two cubes were at the same temperature, how would the average kinetic energy of the particles in iron compare with the average kinetic energy of the particles in aluminum?

There will be no difference in the average kinetic energies

Explanation:

Temperature can be seen as the measure of the average kinetic energy of the molecules in an object. This kinetic energy can sometimes be seen as heat energy. The major way of measuring the kinetic energy (heat energy )of the molecules of a body is by determining the temperature of the body.

Hence, it follows that two bodies with the same temperate have the same kinetic energy of molecules and vice versa, regardless of the make up of the bodies

the density(ratio between mass and volume as m/v) decreases from top to bottom in periodic table group as the size increases and nuclear charge decreases. but in periods density increases from left to right as atom size decreases and nuclear charge increases.