Think of isotopes as the same person wearing different amounts of gear (neutrons), changing their weight but not their identity. Think of isobars as two different people who happen to weigh exactly the same total amount because one is heavier in bone (protons) and the other is heavier in muscle (neutrons).

IsotopE ends in E for Element identity (same atomic number). IsobaR ends in R for weight/mass Result (same mass number).

The atomic number ($Z$) is defined by the number of protons in the nucleus, which dictates the chemical identity of the element. The mass number ($A$) is the sum of protons and neutrons ($A = Z + N$). Isotopes maintain constant $Z$ but vary in $N$, whereas isobars arrive at the same total $A$ by having different combinations of $Z$ and $N$.

Remember that isotopes occupy the same position in the periodic table because they are the same element; isobars occupy different positions.