Atoms and the periodic table

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Atoms and the periodic table

  1. 1. Atoms on the PeriodicAtoms on the Periodic TableTable March 10, 2014March 10, 2014
  2. 2. ObjectivesObjectives 1.1. Describe the present model of theDescribe the present model of the atom explaining electrons, neutrons,atom explaining electrons, neutrons, and protonsand protons
  3. 3. Periodic TablePeriodic Table Atoms make up all matterAtoms make up all matter Elements are any material that is made upElements are any material that is made up of only one type of atomof only one type of atom Elements are organized onto the periodicElements are organized onto the periodic tabletable
  4. 4. Each element is designated an atomicEach element is designated an atomic symbol on the periodic tablesymbol on the periodic table
  5. 5. AtomsAtoms Atoms cannot beAtoms cannot be seen with visible lightseen with visible light Robert BrownRobert Brown First to discover directFirst to discover direct evidence of the atomevidence of the atom
  6. 6. An Atom is made up of three parts:An Atom is made up of three parts:  ProtonsProtons  NeutronsNeutrons  ElectronsElectrons
  7. 7. ElectronsElectrons Electrons surround the nucleus in anElectrons surround the nucleus in an electron cloudelectron cloud Electrons carry a negative chargeElectrons carry a negative charge The atom is mostly empty spaceThe atom is mostly empty space
  8. 8. Electron Cloud ModelElectron Cloud Model
  9. 9. Why don’t we pass through one another?Why don’t we pass through one another? Electrical repulsion – two electrons withElectrical repulsion – two electrons with negative charges will repel each othernegative charges will repel each other
  10. 10. ProtonsProtons Protons and neutrons are bound to theProtons and neutrons are bound to the atomic nucleusatomic nucleus Protons carry a positive chargeProtons carry a positive charge Protons are identified byProtons are identified by Atomic numberAtomic number atom is electrically neutral: Number ofatom is electrically neutral: Number of protons = number of electrons;protons = number of electrons;
  11. 11. NeutronsNeutrons Neutron has no electrical charge, but theNeutron has no electrical charge, but the same mass as a protonsame mass as a proton Protons and neutrons are called nucleonsProtons and neutrons are called nucleons Mass given to each proton and neutron is 1Mass given to each proton and neutron is 1
  12. 12. Atomic MassAtomic Mass • Electrons are so small they areElectrons are so small they are considered negligible in massconsidered negligible in mass • Atomic mass is measured in the unit –Atomic mass is measured in the unit – amuamu  Atomic Mass UnitAtomic Mass Unit Atomic mass on the periodic tableAtomic mass on the periodic table
  13. 13. Agenda Bell work • Review HW • Notes: Mass Number, Isotopes, and Ions • Practice • Have HW out to be checked • Give the protons, electrons, neutrons, and Atomic Mass for the following: – Carbon – Hydrogen – Neon – Zinc – Silver
  14. 14. Mass Number, Isotopes and Ions March 11, 2014
  15. 15. Electrons are so small they areElectrons are so small they are considered negligible in massconsidered negligible in mass Protons and neutrons in the nucleusProtons and neutrons in the nucleus • Atomic mass is measured in the unit –Atomic mass is measured in the unit – amuamu  Atomic Mass UnitAtomic Mass Unit
  16. 16. Atomic MassAtomic Mass Atomic mass on the periodic table –Atomic mass on the periodic table – averageaverage of all its isotopesof all its isotopes Isotope – an Element with differingIsotope – an Element with differing number of neutronsnumber of neutrons
  17. 17. Mass NumberMass Number Mass number = total number of protonsMass number = total number of protons and neutronsand neutrons Identify isotopes by the mass numberIdentify isotopes by the mass number
  18. 18. Isotopic NotationIsotopic Notation Hydrogen – 2Hydrogen – 2  has one proton and one neutronhas one proton and one neutron Hydrogen – 3Hydrogen – 3  has one proton and two neutronshas one proton and two neutrons
  19. 19. Writing Isotopic SymbolsWriting Isotopic Symbols X = element symbolX = element symbol A = Mass NumberA = Mass Number Z = Atomic NumberZ = Atomic Number Total number of neutrons:Total number of neutrons:  Mass Number – Atomic number = number ofMass Number – Atomic number = number of neutronsneutrons
  20. 20. Ions Atoms that gain or lose electrons Lose electrons – positive in charge Gain electrons – negative in charge
  21. 21. Hydrogen that has lost an electron H+1 Hydrogen that has gained an electron H-1

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