Bohr – Electrons not in nucleus: Electrons travel in orbitals around the nucleus Dalton – tiny solid balls Thompson: atom is like a muffin Rutherford: electrons move randomly The History of the Atom Nagaoka - atom structure-like solar system Chadwick - discovered neutron

Atomic Mass = protons + neutrons ATOM STRUCTURE Nucleus Proton(+) Neutron: No Charge Electron(-) Atomic Number: # of protons in element Equal to protons Not in nucleus Atomic Mass = protons + neutrons To find # of Neutrons: Atomic Mass – Atomic #

Organized by Increasing atomic # Left to Right PERIODIC TABLE Organized by Increasing atomic # Left to Right Periods: Horizontal = the # of energy levels. 1st Level: 2 electrons(max) 2nd Level: 8 electrons(max) 3rd Level: 18 electrons(max) 7 Periods Columns: Vertical – Group/Family Similar Properties Same # of Valence Electrons 18 Families Nonmetals – Right (most gas) Metals – Left (most solid) Metalloids – on zigzag line Elements to the left have + ionic charge and elements to the right have - ionic charge Gain Electrons and have an ionic charge of - Loose Valence Electrons and have an ionic charge of +

C PERIODIC TABLE KEYS AND LEGENDS Element Squares Background Color: metal, nonmetal, metalloid Symbol Color: State of Matter 6 C Carbon 12 Atomic # Symbol Element Name Atomic Mass Mendeleev – original table – atomic mass

ELEMENTS / MOLECULES / COMPOUNDS Elements – can’t be broken down Molecule: two or more atoms chemically combined Compound: two or more molecules chemically combined Electron Dot Diagram: # of valence electrons only Covalent Compound: nonmetal +nonmetal Ionic Compound: metal + nonmetal Positive Ion more protons Negative Ion More electrons

Endothermic: absorbs heat – cooling effect Types of Reactions Endothermic: absorbs heat – cooling effect Exothermic: releases heat – warming effect Prefixes Mono – 1 Di – 2 Tri – 3 Quatro – 4 Penta -5 Single Replacement: Fe + H2O Fe3O4 + H2 Chemical Equation Parts: Reactant + Reactant Product

C Cl Cl + Cl Cl Lewis Structures: Electron Dot Diagram Element: Valence electrons only Lewis Structure for Compounds: Chlorine + Chlorine C Cl Cl + Cl Cl

1. Write element symbols for all elements as an addition problem. 2. Write each element with enough room to show electron dot structure 3. Show bonding by venn diagram of electrons in bond 4. Draw and build model of compound 5. Show compound in simple written form with bond. 6. Label as covalent or ionic 7. Write formula for compound