Given that plist has been defined to be a list of 30 elements, add 5 to its last element.

Hi. Your question is quite ambiguous. If the list here follows the periodic table, then I think you are asking for elements 31 to 35. Element 30 is Zinc. This is followed by Gallium (Ga), Germanium (Ge), Arsenic (As), Selenium (Se) and Bromine (Br).