Final answer:
To calculate the new temperature of an ideal gas after removing thermal energy, knowledge of the number of moles and the molar specific heat capacity is required, which we cannot determine with the information provided about the number of atoms alone.
Step-by-step explanation:
To determine the new temperature of an ideal gas after removing 2.8 joules of thermal energy, we can use the first law of thermodynamics, which relates the change in internal energy to the heat added to the system and the work done by the system. However, for this scenario, no work is done, as there is no mention of a volume change. Since we're dealing with an ideal gas, we can also use the equipartition theorem, which states that each mole of a monatomic ideal gas has an internal energy of (3/2)RT, where R is the universal gas constant. We would need the specific number of moles, which can be calculated from the number of atoms given (using Avogadro's number), to proceed further. From there, we can calculate the change in internal energy and subsequently the new temperature. Unfortunately, without the number of moles of the gas or information about the gas's molar specific heat capacity, we cannot provide a specific numerical answer.