Which of the following represents a pair of isotopes? f 1h and 3h g 16o2- and 19f- h 40k and 40ca j 16o2- and 32s2-

Option (F) is the correct answer.

Explanation:

Species which contain same number of protons but different number of neutrons are known as isotope.  

For example, and are isotopes.

These are isotopes of hydrogen and hence, each of them contain 1 proton but the number of neutrons are different.

Whereas the rest of the given species are not isotopes as they contain different number of protons.

When two species contain same atomic mass then they are known as isobars.

For example, and are isobars.

When two different species contain same number of electrons then they are known as isoelectronic species.

For example, both and contain 10 electrons each. Hence, they are isoelectronic.

Thus, we can conclude that and represents a pair of isotopes.

there are two significant figures.