Which of the following is chemically inert (unreactive) ? Select one:

(A) carbon (atomic number 6)

(B) sodium (atomic number 11)

(C) neon (atomic number 10)

(D) oxygen (atomic number 8)

Answer: The chemically inert element is Neon.

Explanation:

Reactivity of an element is defined as the tendency of an element to loose or gain electrons.

Elements are divided into various categories:

Metals are the elements which loose electrons. They are present on the left side of the periodic table. They are present from Group 1 to Group 14 of the periodic table. Non-metals are the elements which gain electrons. They are present on right side of the periodic table. They are present from group 15 to group 17 of the periodic table. Noble gases are present in the farthermost right side of the periodic table. They are present in group 18. They are inert in nature or are unreactive. Transition metals are present in the center of the periodic table from group 3 to group 12. Rare earth metals are present in group 3 from the left. All the elements present in lanthanides series are considered as rare Earth metals.

For the given options:

Option A: Carbon

Carbon is present in Group 14 and Period 2 of the periodic table. It is a metal.

Option B: Sodium

Sodium is present in Group 1 and Period 3 of the periodic table. It is a metal.

Option C: Neon

Neon is present in Group 18 and Period 2 of the periodic table. It is a noble gas.

Option D: Oxygen

Oxygen is present in Group 16 and Period 2 of the periodic table. It is a non-metal.

Hence, the chemically inert element is Neon.