CHEE 3525 Lecture Notes - Lecture 2: J. J. Thomson, Cathode Ray Tube, Cathode Ray
25 Jun 2016
School
Department
Course
Professor
Document Summary
Sizes of atoms: atomic radius, 40 to 270 picometers (pm) a. 1 pm = 10-12m: most of the atomic radius is due to the electron cloud b. Nuclear radius: 0. 001 pm, density is 2x108 metric tons/cm3, 1 metric ton = 1000kg. 4. 2 structure of the nuclear atom: the electron a. Structure of the nucleus: protons, positive charge, mass of 1. 673x10-27kg, the number of protons in the nucleus determines the atom"s identity and is called the atomic number, neutrons, no charge, mass of 1. 675x10-27kg 3. Nuclear forces: short range attractive forces: neutron-to-neutron, proton-to-proton, proton-to-neutron. 4. 3 distinguishing among atoms: atomic number, mass number, and isotopes, atomic number (z, the number of protons in the nucleus of each atom of that element, atoms are identified by their atomic number, because atoms are neutral, Mg = 24. 3050 o = 15. 9994 n = 14. 00674 we use: 24. 31 we use: 16. 00 we use: 14. 01.
