Question

on the periodic table, the elements known as noble gases are all found in
period 2.
period 6.
group 15.
group 18.

Explanation:

Noble gases (helium, neon, argon, krypton, xenon, radon, oganesson) are in group 18 of the periodic table. Groups are vertical columns. Periods are horizontal rows. Group 15 has pnictogens (e.g., nitrogen). Periods 2 and 6 have various elements but not all noble gases.

Answer:

group 18.