Structures of nuclei of three atoms A, B, and C are given below: A has 90 protons and 146 neutrons. 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 and C are isotopes; B and C are isobars
The mass number of A = number of protons + number of neutrons in A = 90+146=236
The mass number of B= number of protons + number of neutrons in B = 92+146 =238
The mass number of C= number of protons + number of neutrons in C = 90+148=238
So, A,B and C can be represented as:
23690A and 23890C are isotopes as they have same atomic number but different atomic mass/mass number
23892B,23890C are isobars as they have same atomic mass/mass number but different atomic numbers.