Question

Which of the following elements readily react with oxygen to form their oxides?

• A. Au and Pt
• B. Ne and Ar
• C. Al and Cu
• D. Cu and Pt

Hint:

Reactive metals like aluminium and copper readily form oxides. Noble metals (Au, Pt) and noble gases (Ne, Ar) are highly resistant to oxidation.

Answer 1

The Correct Option is C

Step 1: Analyze reactivity with oxygen.
Aluminium (Al) is highly reactive with oxygen and forms a protective layer of aluminium oxide (Al\(_2\)O\(_3\)).
Copper (Cu) also reacts with oxygen, though less vigorously, forming copper oxides (CuO and Cu\(_2\)O) over time.
Step 2: Rule out incorrect options.
Option (1): Au (Gold) and Pt (Platinum) are noble metals, known for their low reactivity and resistance to oxidation.
Option (2): Ne (Neon) and Ar (Argon) are noble gases and completely inert under normal conditions—they do not form oxides.
Option (4): Pt, as discussed, is not reactive enough to form oxides readily. Hence, the correct answer is (3) Al and Cu.