Question

an atom has atomic no. 18. why is it considered as noble gas?​

Answer 1

Answer:

Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. ... The complete octet (eight electrons) in the outer atomic shell makes argon stable and resistant to bonding with other elements.

Answer 2

Answer:

it is considered as noble gas because:-

Explanation:

the electronic configuration of this gas would be

K-2

L-8

M-8

Since this gas has successfullly completed its octet therefore it has a stable configuration hence it is a noble gas

BTW, this gas is argon i think so

hope it helps u