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Unit 3 Atomic Structure Slide 2 History of the Atom Watch the Brain Pop on Atomic Model! Slide 3 Atomic Structure + + N N - - NUCLEUS Electrons- outside the nucleus Protons Neutrons Outside the nucleus Slide 4 Complete the following table: Subatomic Particle LocationChargeMass Electron Proton Neutron Slide 5 Complete the following table: Subatomic Particle LocationChargeMass ElectronElectron Cloud (-)0 amu (teeny tiny!) ProtonNucleus(+)1 amu NeutronNucleusNeutral1 amu Slide 6 Reading the Periodic Table * Atomic #: The number of _protons_ in an atom. It equals the number of _electrons_ in a neutral atom. * Mass number = __protons__ + neutrons * # of neutrons = _Mass_#___ - ___atomic number_____ * Atomic Mass: The _average__of all naturally occurring isotopes. Slide 7 Slide 8 Observe the models of atoms at your Lab stations. Use the results and your periodic table to complete the chart and the following questions. Homework: Complete page 6 Slide 9 NOTES: Isotopes and Ions Warm-up: Slide 10 Isotopes: Isotopes - is a version of an atom with the same number of PROTONS, but different number of NEUTRONS. -If an atom is an isotope you name it using the element name followed by the mass number. * Ex: carbon 12 and carbon -14 - Writing Isotope Symbols: 1. Write the atomic symbol for the element 2. To the top left of the symbol write the mass # of the isotope. 3. Beneath that (to the bottom left of the symbol). Write the atomic number of the element. Slide 11 Ex: Label the following C 14 6 Carbon-14 is written like this: Mass # Atomic # Element Symbol Slide 12 Isotope Examples: C and C 14 6 12 6 How many protons does Carbon-14 contain? 6 How many neutrons does Carbon-14 contain? 14-6 = 8 How many protons does Carbon-12 contain? 6 How many neutrons does Carbon-12 contain? 12-6= 6 Slide 13 * Atoms as a rule are all neutral in charge, meaning that the number of protons and electrons in the atoms are equal. Ions: Ions are charged atoms (+ or -) Formed when an atom GAINS or LOSES electrons Slide 14 Ions Cations Positively (+) charged atoms Form by LOSING electrons Usually formed by metals ExamplesLithium - 7 Protons: 3 Neutrons: 4 Charge: 1+ Electrons: 2 + Slide 15 Ions Anions Negatively (-) charged atoms Form by GAINING electrons Usually formed by nonmetals Examples Sulfur - 32 2-2- Protons: 16 Neutrons: 16 Charge: 2- Electrons: 18 Slide 16 Page 9 -10 Complete the table as directed on Pg. 9. Complete the chart and answer the questions on Pg. 9 in group of 2 (no larger!). Homework: Pg. 10 Slide 17 Atom# Isotope Symbol Atom name with mass # #Protons #Neutrons #Electrons Atomic Number Mass Number Neutral/Isotop e/Ion Charge 1 Neutral0 2 0 3 0 4 0 5 0 6 7 8 9 10 11 12 Slide 18 Isotopes and Average Atomic Mass * Compare & contrast Mass Number and Atomic Mass: Slide 19 Atomic Mass Calculations Atomic mass is the weighted average of the masses of all naturally occurring isotopes. Atomic Mass= [(Percent Abundance) x (Mass of Isotope)] = take the sum of; add them all up at the end! Sample Calculations together.. Slide 20 Atomic Structure- Inside the Nucleus Protons Positively (+) charged particles Equal to the atomic number Identity of atoms is based on # of protons in Nucleus Contribute to the mass of the atom Proton mass = 1amu amu= atomic mass unit Slide 21 Atomic Structure- Inside the Nucleus Neutrons Neutral particles (no charge) Help hold nucleus together; contribute to stability Neutrons + Protons= mass number Neutron mass = 1amu Slide 22 Atomic Structure- Outside the Nucleus ( Electron Cloud) Electrons Negatively ( - ) charged particles Responsible for the CHEMICAL PROPERTIES of the atom In a neutral atom (no charge), protons=electrons Very little mass ~0 amu Slide 23 Reading the Periodic Table Elements C Carbon 6 12.01 Atomic number Atomic Mass Element Symbol = # Protons (element identity!) = weighted average of isotope atomic masses Slide 24 Complete the following table: Complete Symbol Mass Number Atomic Number ProtonsNeutronsElectrons 1614 Se 70 34 Slide 25 Complete Symbol Mass Number Atomic Number ProtonsNeutronsElectrons Si 14+16 = 30 14 1614 Se7034 70-34 = 36 34 30 14 70 34 Slide 26 = Cations +=+= Slide 27