Which of the following elements would be the most stable (unreactive)? 1 ) Fr
2) Fe
3) H
4) Ne

4) Ne

Chemistry

Atomic Structure

The most stable (unreactive) elements are found in group 18. They are known as the Noble Gases.

Noble Gases are inert, meaning they do not react easily with other elements. The reason is because their valence electron shells are filled.

Therefore, our best answer is 4) Ne.

Explanation:

On the Periodic Table, the last group of elements are the Noble Gases. These are the most unreactive or stable elements.

According to the Octet Rule, atoms always want to have 8 valence electrons. The Noble Gases already satisfy this rule and have full outer shells, therefore they don't react with other elements often.

The Noble Gases are helium (He) , neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), radon (Rn), and oganesson (Og).

The only answer choice that is a Noble Gas is 4. Ne

neutrons are in the middle of the atom and the electrons, which are much smaller.