In a Monatomic Gas?

It is usually applied to gases: a monatomic gas is one in which atoms are not bound to each other. Examples at standard conditions include the noble gases argon, krypton, and xenon, though all chemical elements will be monatomic in the gas phase at sufficiently high temperatures.

What is a monatomic ideal gas?

An ideal gas composed of single atoms. Examples include the noble gases argon, krypton, and xenon.

Is monatomic gas unreactive?

Monatomic gas exists as a single atom and does not bound to each other. They are stable at standard room temperature. There is no chemical bond involved in these gases. They are very unreactive due to the completely full outer valence shell.