13. Which of the following elements is NOT a noble gas? A krypton

Bargon

C chlorine

D helium

Chlorine is a halogen, not a noble gas.

Explanation:

The last two groups of the periodic table is named as halogen family and Nobel gas family.

The group 17 is composed of gases collectively called as halogen and it includes the following gases:

Fluorine Chlorine Bromine Iodine Astatine Tennessine

The group 18 is composed of elements which are collectively called as Nobel gas and it includes:

Helium Neon Argon Krypton Xenon Radon Oganesson

The below given table shows the halogen and Nobel gas in the periodic table.