Question

Imagine that you wanted to make a time capsule in which you would seal important artifacts from your life (pictures, poems, a lock of your baby hair, etc.), to be opened by your heirs 1,000 years from now. To prevent these artifacts from decaying, you want to fill the capsule with a gas that would be least reactive. Which of these gases would you choose: oxygen gas (O2) carbon dioxide (CO2), argon gas (Ar), or hydrogen gas (H2)? (The atomic numbers of the atoms in these molecules are as follows: oxygen = 8; carbon = 6; argon = 18; and hydrogen = 2.)

Answer 1

Argon gas

Step-by-step explanation:

Between the options given, argon gas is the least reactive. Argon is known as a noble gas, this means that it is located in the group 18 in the periodic table. These gases are known for their low reactivity, under most circumstances.

The electronic configuration of argon helps us see why that is the case: With an atomic number of 18, it has an electronic configuration of 1s² 2s² 2p⁶ 3s² 3p⁶. This means the most external orbital is filled with electrons, meaning that there are not unpaired electrons able to react with other substances.