Question

Question 11
In a sample of ethyl ethanoate $\left(C{H}_{3}COO{C}_2{H}_5\right)$ the two oxygen atoms have the same number of electrons but different number of neutrons; which of the following is the correct reason for it?

(a) One of the oxygen atoms has gained electrons
(b) One of the oxygen atoms has gained two neutrons
(c) The two oxygen atoms are isotopes
(d) The two oxygen atoms are isobars.

Answer 1

The answer is (c).
The two O-atoms in $C{H}_{3}COO{C}_2{H}_5$ can have different number of neutrons only if the two O-atoms are isotopes. It is because, isotopes of an element have the same number of protons (and electrons) but different number of neutrons.