noun
( chemistry ) the number of protons in the nucleus (= centre) of an atom, which is characteristic of a chemical element. Elements are placed in the periodic table according to their atomic numbers.
noun
( chemistry ) the number of protons in the nucleus (= centre) of an atom, which is characteristic of a chemical element. Elements are placed in the periodic table according to their atomic numbers.
Oxford Advanced Learner's English Dictionary. Оксфордский английский словарь для изучающик язык на продвинутом уровне. 2005