Answer:
Radon
Explanation:
Radon is present in last group of periodic table which is eighteen.
It is the member of noble gases.
The member of eighteen group are inert.
Radon have complete octet and also inert.
Its atomic mass is 222 amu.
Its atomic number is 86.
Electronic configuration:
Rn₈₆ = [Xe] 4f¹⁴ 5d¹⁰ 6s² 6p⁶
