Question

Structures of nuclei of three atoms A, B and C are given: A has 90 protons and 146 neutron; B has 92 protons and 146 neutrons; C has 90 protons and 148 neutrons. Based on the above data, which of these atoms are isotopes and which are isobars?

• A. A and C are isotopes; B and C are isobars
• B. A and B are isotopes; A and C are isobars
• C. B and C are isobars; A and B are isotopes
• D. A and C are isotopes; A and B are isobars

Answer 1

The correct option is A

A and C are isotopes; B and C are isobars

Isotopes are the atoms of the same element having the same atomic number but the different mass number but isobars are the atoms of different elements having the different atomic number but the same mass number.

${}^{236}{A}_{90}$, ${}^{238}{B}_{92}$, ${}^{238}{C}_{90}$
A and C are isotopes (having the same atomic number) B and C are isobars (having the same mass number)