Which of these properties is the best one to use for identification of an element? the number of neutrons in the atomic nucleus the number of protons in the atomic nucleus the number of isotopes that are formed by the element the number of charges on ions of the element

Elements are identified by their atomic number on the periodic table which is equal to the number of protons in the atomic nucleus. Isotopes of an element are formed when neutrons are added or removed from the element. The number of charges on an ion of the element corresponds how many valence electrons the atom has that it either is ready to give up (forms a positive ion) or ready to accept more electrons (forms a negative ion).