Question:
In a sample of methyl ethanoate $\left(\mathrm{CH}_{3} \mathrm{COOCH}_{3}\right)$ 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.
Solution:
(c) The two oxygen atoms are the isotopes. These are the different atoms of the same element which have same number of electrons (or atomic number) but different number of neutrons.