Question

Which of the following is not a Noble gas?
A. Helium
B. Neon
C. Argon
D. Hydrogen

Answer 1

Hint: Noble gas means any of the gaseous elements which occupy Group 0(18) of the periodic table. They exhibit great stability and very low reaction rate.
Complete step by step solution:
Noble gases are generally inert gas that exhibit great stability and have generally full filled electronic configuration.
They belong to group 18 of the periodic table.
Group 18 of the periodic table includes He, Ne, Ar, Kr, Xe and Rn.
Therefore, we can conclude that Hydrogen is not a Noble gas hence, option D is correct.

Additional information:
Noble gases are colorless, odorless, tasteless, and nonflammable gases under standard conditions.
In the periodic table, the noble gases are arranged according to their boiling point
The outer shell of valence electrons is considered to be “full” in noble gases, giving them little tendency to participate in chemical reactions.
Noble gases are widely used in different fields, from incandescent lighting to excimer lasers.
Xenon finds application in medical imaging of the lungs through hyperpolarized MRI.
Radon which is highly radioactive and is only available in very less amounts is used in radiotherapy.
Note: It's our misconception that not even a single noble gas forms a compound. Noble gas named as Xenon can form compounds of oxygen and fluorine because the electron attraction to the nucleus is weaker and hence the valence electron of Xe is attracted by fluorine or oxygen.