Question

The neutron was discovered by:

Hint:

He used alpha particles fired at beryllium to reveal this uncharged particle.

Answer 1

Step 1: Recall the structure of the atom before this discovery.
By the early twentieth century, scientists knew atoms contained protons and electrons, but experiments showed the atomic mass could not be explained by these particles alone.
Step 2: Identify the discoverer.
James Chadwick, a British physicist, discovered the neutron in 1932 through experiments involving alpha particles striking beryllium, which released a new, uncharged particle with a mass close to that of a proton.
Step 3: Note the significance.
This discovery completed the basic picture of the atomic nucleus as made of protons and neutrons, and Chadwick received the Nobel Prize in Physics in 1935 for this work.
Final Answer: James Chadwick.