The correct answer is - grandparent and grandchild.
Jim has a daughter, The name of his daughter is Bertha. Bertha also has children, two daughters, one of which is Penny. Since Jim's daughter is Bertha, than the children of Bertha are his grandchildren, thus Penny is Jim's grandchild, and Jim is Penny's grandparent.
The periodic table is arranged by number of protons/electrons which is the same for all isotopes of an element. <u>A different isotope will have a different number of neutrons only, which does not qualify it for a separate space on the periodic table.</u>
