George is writing an essay about the role of observation and inference in the development of the atomic theory. He wants to explain why it was more difficult to observe the presence of neutrons in atoms. Which two statements should he include in his essay?

Electrically neutral

High penetration

Explanation:

Electrically neutral: The deflection of an electron beam in the presence of a magnetic field was the first step towards the discovery of the electrons. This was because the electrons were negatively charged. Then there had to be some positively charged particles in an atom so that the atom is electrically neutral, thus leading to the discovery of the proton. But the neutron is neutral. Hence, it wasn't deflected in the presence of any magnetic or electrical fields. Therefore, neutrons were hard to detect. High penetrating effect: Neutron beam is highly penetrating, much more than a beam of protons (like the alpha emission) or the electron beam (beta emission). Therefore, neutron beam was initially mistaken as the gamma emissions.