Question

Which of these elements is a noble gas? A. hydrogen (H) B. barium (Ba) C. nitrogen (N) D. krypton (Kr) E. bromine (Br)

Answer 1

Answer: The correct answer is Option D.

Explanation:

Noble gases are defined as the gases which have stable electronic configuration and is highly nonreactive. These belong to Group 18 of the periodic table.

For the given options:

• Option A: Hydrogen (H)

The electronic configuration of hydrogen = $1s^1$

This element belongs to Group 1 and is known as alkali metal.

• Option B: Barium (Ba)

The electronic configuration of barium = $[Xe]6s^2$

This element belongs to Group 2 and is known as alkaline earth metal.

• Option C: Nitrogen (N)

The electronic configuration of nitrogen = $1s^12s^22p^3$

This element belongs to Group 15 and is known as p-block element.

• Option D: Krypton (Kr)

The electronic configuration of krypton = $[Ar]4s^23d^{10}4p^6$

This element belongs to Group 18 and is known as noble gas.

• Option E: Bromine (Br)

The electronic configuration of bromine = $[Ar]4s^23d^{10}4p^5$

This element belongs to Group 17 and is known as halogen.

Hence, from the above information, the correct answer is Option D.

Answer 2

Krypton is a noble gas! Hope this helps!