Question

what do the pair of symbols $_{92}^{235}u$ and $_{92}^{238}u$ represent?
a) allotropes
b) radioactive tracers
c) isotopes
d) radiation particles

Explanation:

Isotopes are atoms of the same element with the same number of protons but different numbers of neutrons. The given symbols $^{235}_{92}U$ and $^{238}_{92}U$ are uranium atoms with atomic number 92 (same number of protons) and different mass - numbers (235 and 238, indicating different numbers of neutrons). Allotropes are different forms of the same element in the same physical state. Radioactive tracers are radioactive substances used to track processes. Radiation particles are particles emitted during radioactive decay.

Answer:

C. isotopes