Question

Which one of the following has the greatest mass?
a.) Alpha particle
b.) Beta particle
c.) Neutron
d.) Gamma-ray
e.) Positron

Answer 1

Hint: As we know mass is commonly measured by how much something weighs. Now, just find the number of subatomic particles and their mass in the species provided and try to figure out what could be the possible order of masses.

Complete step by step answer:

First, you should be aware of the mass of the proton (mp), which is 1.6726×${10}^{-27}$ kg,
An electron has a mass (me) 9.1094×${10}^{-31}$ kg which is approximately 1/1836 that of the proton. The mass of a neutron (mn), 1.6749×${10}^{-27}$ kg is slightly larger than that of a proton.
The mass of the hydrogen nucleus is 1.7 x ${10}^{-27}$ kg. The heaviest of these particles is the neutron.
Alpha particle has two protons and two neutrons bound together into a particle identical to a helium nucleus. They are generally produced in the process of alpha decay, but may also be produced in other ways, that makes its mass to be equal to 2mp + 2mn.
The beta particle has the same mass equal to an electron, which is equal to me.
Neutrons have mass equal to mn.
Gamma-rays are massless. A gamma-ray (also known as gamma radiation) is NOT a particle. It's a high energy wavelength of light also known as a photon. Photons are massless, as they are pure energy.
The positron or antielectron is the antiparticle of the antimatter counterpart of the electron. It has a mass equal to me.

From all these statements we can conclude that alpha particles have the greatest mass among all the options given.

Therefore, we can conclude that the correct answer to this question is option A.

Note: We can also arrange these species in the increasing order of their masses -
Mass of gamma-rays < Mass of electron = Mass of positron < Mass of neutron < Mass of alpha particle