原子结构与原子理论 Atomic Theory and Atomic Structure.ppt

* Department of Chemistry Hon Man Lee (李漢文) Tel: 3517 (office); 3523 (lab) 3/F Chemistry Building 自然科學概論(化學) .tw/leehm/contents/enter.htm leehm@.tw * Atomic Theory and Atomic Structure 原子理論與原子結搆 * Atomic Theory of Matter John Dalton in 1808 All matter is composed of small particles called atoms. An atom (原子): indivisible, retain its identity during chemical reactions An element (元素): A type of matter of only one kind of atom, e.g. hydrogen (H), oxygen (O) * What is a compound? A compound(化合物): A type of matter of atoms of two or more elements chemically combined in fixed proportions, e.g. water (H2O, CH4) (ii) molecular compound (分子化合物), e.g. H2O (iii) ionic compound (離子化合物), e.g. sodium chloride, 氯化鈉 (Na+ Cl-) * What is a chemical reaction? A chemical reaction (化學反應): Rearrangement of the atoms present in the reactant to give new chemical combinations present in the product Equation (反應式): 2H2 + O2 ? 2H2O Reactant Product * A balanced equation Atoms are not created, destroyed, or broken!!! H2 + O2 –--//-- NaCl A balanced equation H2 + O2 –--//-- H2O No. of H atoms in right hand side = No. of H atoms in left hand side ? Same to the atoms of other elements * Sub-atomic particles Dalton did not know there were sub-atomic particles in the atoms. Dalton atomic theory in 1808. * The structure of the atom Discovery of the electron (1897): J. J. Thomson (British) The nuclear model of the atom (1911): Ernest Rutherford (British) * The structure of the atom Atom: nucleus (原子核) + electrons (電子) Nucleus : neutrons (中子), protons (質子), For example, H = 1 proton + 1 electron * The hydrogen atom Electron: mass = 9.10939 x 10-31 kg, charge = -1 Proton: mass = 1.67262 x 10-27 kg, charge = +1 Neutron: mass = 1.67493 x 10-27 kg, charge = 0 Mass = 質量 Isotope (同位素) 重氫, 氘 1. Mass of p/n = 1833 e 2. mass of proton ≈ mass of neutron Notice the accuracy!! * Isotopes (同位素) atoms whose nuclei have same atomic numbers but different mass numbers same n