Chemistry - PERIODIC TABLE Question with Solution | TestHub

The species H¹, D², and T³ are isotopes of hydrogen. Isotopes of an element have the same number of protons and electrons but differ in the number of neutrons. Atomic size is primarily determined by the electron cloud, which is governed by the number of electrons and the nuclear charge. Since all three species have one proton and one electron, their electron configurations are identical. Therefore, their atomic sizes are essentially the same.

The correct answer is D.