Final answer:
The subatomic particles with a single negative charge that orbit the nucleus are electrons. Protons and neutrons are found in the nucleus, with protons carrying a positive charge and neutrons being neutral. Isotopes refer to variants of elements with different neutron counts, not charged particles.
Step-by-step explanation:
The subatomic particles that possess a single negative charge and surround the nucleus are the electrons. The nucleus of an atom is positively charged and contains protons, which have a positive electric charge, and neutrons, which have no charge. Electrons orbit the nucleus, filling the mostly empty space around it. These particles are fundamental to the structure of an atom, and the interaction between protons and electrons accounts for most of the charged nature of matter.
The other options provided in the question represent different subatomic particles: protons, which have a positive charge and are found in the nucleus; neutrons, which are neutral and also reside in the nucleus; and isotopes, which refer to atoms of the same element that have different numbers of neutrons. Therefore, the correct answer to the question is d. electrons.