1024 atoms of helium (He) gas, as in a large party balloon, and 1024 atoms of copper (Cu), as in a stack of Cu pennies, are in the same room and thus have the same temperature. Which group of atoms has the most thermal energy?

Helium atoms has higher thermal energy in comparison to copper atoms present in solid copper penny under same temperature.

Explanation:

Thermal energy of the object is defined as an internal energy due to kinetic energy of atoms or molecules of the object.The atoms or molecules of hotter object has higher energy than the cooler objects.

The thermal energy in an object is produced on rising the temperature due to which atoms or molecules moves fast and collides with each together.

Thermal energies of solid is least, moderate in liquids and in gases it is maximum thus because is solids atoms or molecules just vibrate due to which they have low kinetic energy where as in gases atoms or molecules are free to move with higher kinetic energy.

So, according to question helium atoms has higher thermal energy in comparison to copper atoms present in solid copper penny under same temperature.

the answer would be b i believe