CHEM 101 Lecture Notes - Lecture 3: Unified Atomic Mass Unit, Nuclear Chemistry, Nuclear Reaction
Document Summary
Atomic number (z): the (cid:374)u(cid:373)(cid:271)e(cid:396) of p(cid:396)oto(cid:374)s i(cid:374) a(cid:374) ato(cid:373)"s (cid:374)u(cid:272)leus: e(cid:395)ui(cid:448)ale(cid:374)t to the (cid:374)u(cid:373)(cid:271)e(cid:396) of ele(cid:272)t(cid:396)o(cid:374)s a(cid:396)ou(cid:374)d the ato(cid:373)"s (cid:374)u(cid:272)leus, gi(cid:448)es a(cid:374) ato(cid:373) its" ide(cid:374)tity. Mass number (a): the sum of the number of protons and the number of neutrons in an ato(cid:373)"s (cid:374)u(cid:272)leus. Isotope: atoms with identical atomic numbers but different mass numbers: #n=#m-#a. Atomic mass: the (cid:449)eighted a(cid:448)e(cid:396)age of the isotopi(cid:272) (cid:373)asses of the ele(cid:373)e(cid:374)t"s (cid:374)atu(cid:396)ally occurring isotopes i. e. the mass of one atom of c-12 is defined to be 12amu (atomic mass units) Very small volume compared to volume of the atom. Composed of protons and neutrons that are tightly held together: p+n= nucleons. Nuclear chemistry: the study of the properties of reactions of the atomic nuclei= mass number. Nuclear reaction: a reaction that changes an atomic nucleus. Release of tiny, high energy particles from an atom. Types of radioactive rays: rutherford discovered there were 3 types of radioactivity.
