Mary J. Bojan Chem 110 Chapter 6 Part 1 Structure of the atom • What IS the structure of an atom? • What are the properties of atoms? REMEMBER: structure affects function! • Important questions: Where are the electrons? What is the energy of an electron? Chapter 6 Part 1 Dual Nature of Light !" =c E = h " Line Spectrum Bohr Model of Hydrogen Atom 1
Why do we start with Chapter 6? Overview of Chem 110 Key themes: structure effects function (properties). How do we know about atoms, etc.? Structure of atom Ch. 6 Properties of Atom Ch. 7 How atoms bond to form molecules Ch. 8 Structure of molecules Ch. 9 Properties of molecules Ch. 10, 11, 13 Molecules REACT! Ch. 3, 4, 10 Rules that govern reactions Thermodynamics – (think energy) Ch. 5 Equilibrium Ch. 15 Mary J. Bojan Chem 110 2
What is the structure of an ATOM? COMPONENTS OF ATOMS mass charge (a.m.u.) (a.u.) proton p electron e neutron n Neutral Ion Mary J. Bojan Chem 110 F 19 9 + K 39 19 3
ISOTOPES • atomic number = ??? • DEFINES identity of element For a given element, number of protons is fixed, but number of neutrons can vary. Isotopes: Mary J. Bojan Chem 110 Cl 35 17 Cl 37 17 4
The Atomic Mass Scale We define: mass of 12 C = exactly 12 amu. Use ISOTOPE RATIOS to find Average Atomic Masses Mary J. Bojan Chem 110 5
The Atomic Mass Scale Another definition: 1 mole of 12 C has a mass of 12 g What is a mole?