WARM UP 1. Radium is an element found in Group 2 and Period7. In a normal radium atom, how many electron energy levels are present? A. 2 C. 7 B. 6 D Which of the following is smaller than a single atom? A. Proton C. Element B. Molecule D. Solution 3. Which of the following is a chemical symbol representing an element? A. C C. CO2 B. CO D. H2O 4. Positive, Negative or Neutral? Proton _________ Neutron _________ Electron _________

February 24,2011

Chemical Properties Reactivity – describes how likely an element is to react and form bonds with other elements. Most reactive metals are the alkali metals in Group 1. *Not including Hydrogen Inert – unable to react chemically Noble gases, Group 18, least reactive of all elements – most stable family of elements

Conservation of Matter Reactants – substances that are present before the reaction occurs and that are changed by the reaction Products – substances present after the reaction takes place LAW OF CONSERVATION OF MATTER States that matter cannot be created or destroyed; Matter may change form to another Atoms might be rearranged to form new substances; The same number of atoms exists before and after the changes Total mass of the matter does not change

Formation of Rust Properties of Iron - Hard, solid, gray-colored metal Properties of Rust - Flaky, orange-red solid Iron + Oxygen Iron Oxide 4Fe + 3O 2 2Fe 2 O 3 No new atoms are added and no atoms are destroy Mass of Reactants = Mass of Products Law of Conservation of Matter

Chemical Equations Reactants Products Mass of Reactants = Mass of Products Tin + Hydrogen Fluoride Tin fluoride + Hydrogen 118.7g g = g + ? Na 2 O + H 2 O ? How many O, Na, H atoms must be present in the product that forms from this reaction?