Question

early discovery and development of isotopes
for well over a century, scientists have understood that many of the earths elements occur in different atomic configurations or isotopes - and some of these possessed radioactive qualities. research into the nature and characteristics of radioisotopes reached a crucial milestone in the 1930s with ernest lawrences invention of an improved version of the particle accelerator, known as the cyclotron. scientists soon discovered that by bombarding different materials with cyclotron - produced high energy beams it was possible to obtain small quantities of artificial radioisotopes.
what different subatomic particles would need to collide in the cyclotron to create different nuclei / isotopes?

Explanation:

Step1: Recall subatomic particles

Subatomic particles include protons, neutrons, and electrons. In the context of creating different nuclei/isotopes in a cyclotron (which is related to nuclear reactions), electrons are not involved in changing the nucleus. Protons are positively charged and neutrons are neutral.

Step2: Determine relevant particles

Nuclei are made up of protons and neutrons. To create different isotopes (which have the same number of protons but different numbers of neutrons) or different nuclei (which can have different numbers of protons and neutrons), the subatomic particles that collide are protons and neutrons. For example, if you bombard a target nucleus with protons or neutrons (or both in some complex reactions), you can change the composition of the nucleus.

Answer:

Protons and neutrons.