Lecture 1 Outline of Last Lecture I. Started talk on syllabus- first day Outline of Current Lecture II. Introduction to Chemistry a. Essential Elements III. Periodic Table a. Atomic number b. Mass number IV. Modified Atoms a. Ion b. Isotopes V. Bonds a. Ionic b. Covalent Current Lecture VI. Element: a. Substance that cannot be broken down into other substances by a chemical reaction VII. Compound: b. Two or more different elements combined in a fixed ratio VIII. 96% of living matter is c. Hydrogen (H) d. Oxygen (O) e. Nitrogen (N) f. Carbon (C) i. Remember Acronym HONC IX. Atom: a. Smallest unit of an element b. Atomic number i. Number of protons in the atom’s nucleus c. Atoms can undergo changes i. Modified atoms 1. Add or loose an electron 2. Ion- atom with an unpaired proton or electron 3. Isotopes- atom with the same number of protons but different number of neutrons a. Some are radioactive(unstable) X. Mass Number Life 102a. Number of protons + neutrons XI. Electron Shells a. Shells are found at different distances from nucleus i. Shell 1: Can hold 2 electrons ii. Shell 2: Can hold 8 electrons b. Noble Gases i. Very stable because all shells are filled XII. Valence Shell a. Outer shell that contains electrons b. Atoms want a full valence shell to be more energetically stable XIII. Ionic Bond a. Between oppositely charges ions i. Cation (positive charge) and Anion (negative charge) b. i.e. NaCl XIV. Covalent Bond a. Two atoms that share an electron pair b. i.e. H2O c. Polar covalent bond i. Electrons not equally shared between two atoms XV. Hydrogen Bond a. Two molecules that attract each other b. Weak temporary bond XVI. Mass Conservation Law a. All atoms present in the reactants are still present in