The values of the neutron drip line are only known for the first ten elements, hydrogen to neon. For oxygen (Z = 8), the maximal number of bound neutrons is 16, rendering O the heaviest particle-bound oxygen isotope. For neon (Z = 10), the maximal number of bound neutrons increases to 24 in the heaviest particle-stable isotope Ne. The location of the neutron drip line for fluorine and neon was determined in 2017 by the non-observation of isotopes immediately beyond the drip line. The same experiment found that the heaviest bound isotope of the next element, sodium, is at least Na. These were the first new discoveries along the neutron drip line in over twenty years.