Which of the following elements would have the lowest oxidation number?

• A. Indium, In
• B. Strontium, Sr
• C. Argon, Ar
• D. Manganese, Mn

Answer: (C)

Verified step by step guidance

1. Understand the concept of oxidation numbers: Oxidation numbers are used to indicate the degree of oxidation of an atom in a chemical compound. The oxidation number of an element in its elemental form is always zero.
2. Identify the oxidation numbers of the given elements: Argon (Ar) is a noble gas and typically does not form compounds, so its oxidation number is zero. Indium (In) typically has oxidation numbers of +1 or +3. Strontium (Sr) usually has an oxidation number of +2. Manganese (Mn) can have multiple oxidation states, ranging from -3 to +7.
3. Compare the oxidation numbers: Since Argon is a noble gas and does not form compounds, its oxidation number remains zero, which is the lowest possible oxidation number compared to the other elements listed.
4. Consider the chemical behavior of noble gases: Noble gases like Argon are chemically inert and do not readily participate in chemical reactions, which is why their oxidation number is zero.
5. Conclude based on the comparison: Argon, being a noble gas with an oxidation number of zero, has the lowest oxidation number among the elements listed.