Question

For each pair of elements listed, predict which one has more stable isotopes: (a) Pd or Ag, (b) Na or Mg, (c) I or Xe.

Answer 1

General Rules:

1) Element containing even protons and odd number of neutrons are more stable in isotope formation

2) Elements containing complete octets are more stable due to magic number formation

3) Elements having proton to neutron ratio closest to 1 are more stable

a) Pd has more stable isotopes than Ag since it is having even atomic number, 4d10 configuration and closer proton to neutron ratio

b) Mg is having 12 protons whereas Na has 11 protons, the proton to neutron ratio is exact 1 and has 3s2 full configuration, so Mg will have more stable isotopes than Na

c) Xenon has more, even protons, noble gas configuration with all octet's filled.

Note - Post any doubts/queries in comments section.