18 explain what happens to the average kinetic energy, thermal energy, and temperature of a substance when the particles in the substance slow down.

answer:

the particles in a substance slow down when the average kinetic energy of the particles decreases. as the average kinetic energy decreases, the internal energy decreases, and so the thermal energy decreases. as the thermal energy of the substance decreases, the temperature decreases.

explanation:

one state would change   like louisiana to texas. thats a change

explanation:

considering the question as per the attachment

here we can see that the radon nuclide has 222 as the atomic mass number and 86 as the atomic number.

when it undergoes nuclear fission it gives polonium which has atomic mass number as 218 and atomic number will be 84 along with a helium nucleus which has 4 atomic mass number and 2 as its atomic number.

222 = 218 + 4 (atomic mass number)

86 = ? + 2; therefore ? = 86-2 = 84.

the atomic mass number of polonium will be 84.