Answer: So let's say you climbed on top of a tree in your backyard and decided you wanted to drop some acorns down at people. We will assume there is no air resistance (we live in some vacuum world) and remembering that the total mechanical energy of the system is constant
Answer: Kinetic Energy of the atoms also increases.
Explanation: We are given that the temperature of the gas increases.
Relation between kinetic energy and temperature follows:

where, K = Average Kinetic energy
R = Gas constant
T = Temperature
= Avogadro's number
As seen from the relation above, the Kinetic energy of the gas is directly proportional to the temperature, hence as the temperature increases, kinetic energy of the atom also increases.
The nuclear reaction occurring is known as alpha-decay, and during this process, an alpha particle is released from a heavy radioactive nucleus to form a lighter more stable nucleus. The alpha particle is equivalent to a helium nucleus, which means it contains 2 protons and two neutrons (net charge of +2)
The decay equation is:
Rn → Po + α