Answer:
O2
Explanation:
A compound is made of two or more chemical elements. With that in mind, O2 is only one element: oxygen.
Answer:
D. O2
Explanation:
First, let’s define a compound.
A compound is a substance made when 2 or more elements are chemically combined in a fixed ratio.
Now, let’s examine the answer choices.
A. NaCl
• This has sodium (Na) and chlorine (Cl) so it is a compound.
B. N2O
• This has nitrogen (N) and oxygen (O). This is a compound.
C. CO2
• This has carbon (C) and oxygen (O) so this is also a compound.
D. O2
• This only has oxygen (O). A compound needs two or more elements, so this is not a compound.
Therefore, the correct answer is D. O2
