Answer : The correct option is krypton (Kr).
Explanation :
Noble gas : It is a group which is present at last in the periodic table and they belongs to group 18.
The general electronic configuration of noble gas is [tex](ns^2np^6)[/tex].
The noble gas contains six elements which are helium, neon, argon, krypton, xenon and radon.
According to the question,
- Hydrogen belongs to group 1 which is a alkali metal.
The general electronic configuration of hydrogen is [tex](ns^1)[/tex].
- Barium belongs to group 2 which is an alkaline earth metal.
The general electronic configuration of barium is [tex](ns^2)[/tex].
- Nitrogen belongs to group 15 which is a non-metal.
The general electronic configuration of nitrogen is [tex](ns^2np^3)[/tex].
- Bromine belongs to group 17 which is a halogen.
The general electronic configuration of bromine is [tex](ns^2np^5)[/tex].
- Krypton belongs to group 18 which is a noble gas.
The general electronic configuration of krypton is [tex](ns^2np^6)[/tex].
Therefore, the correct answer is krypton (Kr).
