Here's why:

* Noble Gases: All three elements belong to Group 18 (VIIIa) of the periodic table, also known as the noble gases. This group is characterized by having a full outer shell of electrons, making them extremely stable and unreactive.

* Similar Chemical Behavior: Helium, neon, and argon are all colorless, odorless, and tasteless gases at room temperature. They exist as single atoms and do not readily form chemical bonds with other elements.

* Similar Physical Properties: They have low boiling points and melting points, and they are poor conductors of heat and electricity.

While neon and argon are similar to helium, there are some differences in their properties:

* Atomic Size: Neon and argon are larger atoms than helium, with more protons and neutrons in their nuclei.

* Density: Neon and argon are denser than helium.

* Reactivity: While all three are very unreactive, neon and argon are even less reactive than helium.

Overall, neon and argon are the two elements that most closely resemble helium in terms of their chemical and physical properties due to their shared position as noble gases with a stable electron configuration.