Which of the following forms of radiation particles has the greatest mass?

alpha particle

beta particle

neutron

gamma

The particle with the greatest mass is:

The alpha particle.

Explanation:

The mass of the Alpha Particle is considered to be 4 amu, which is the biggest of all these options.

The mass o the beta particle is considered to be 1/2000 amu which is considered to be the third place of the elements shown.

The neutron has a mass of 1 amu which makes it larger than the beta particle's mass and brings it to the second place of our rank.

The gamma particle mass is considered to be 0 because it is made of pure energy. Therefore it occupies the fourth place in our rank.

your answer is a. the enthalpy of formation for a pure element in its standard state is always positive.