Gujarat BoardEnglish MediumSTD 9ScienceAtoms and Molecules1 Mark
MCQ
Which of the following is not a molecule?
✓
$O$
B
$O_2$
C
$CO_2$
D
$N_2$
✓
Answer
Correct option: A.
$O$
A molecule may be homonuclear, that is, it consists of atoms of a single chemical element, as with oxygen $\left( O _2\right.$ or $\left.N _2\right)$, or, it may be heteronuclear, a chemical compound composed of more than one element, as with water $\left( H _2 O\right.$ or $\left.CO _2\right)$. Out of all the options, $O$ represents a single oxygen atom and not a molecule.
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