Question

Two atoms A and B have the following nuclear composition:
Atom A Atom B
17 protons 17 protons
18 neutrons 20 neutrons
17 electrons 17 electrons
a) What is the mass numbers and atomic numbers of A and B.
b) What is the relation between the two chemical species?
c) which element or elements do they represent?

Answer 1

1. Mass number or A = sum of protons and neutrons

Mass number of A = 35 and that of B is 37

2. They have the same atomic number but different atomic mass and so are isotopes.

3. Chlorine, Cl