1. Physical Science Ch. 18

2. Section 1 Structure of the Atom

3. ElementElement –Matter that is composed of one type of atom. AtomAtom –The smallest particle of matter that retains the property of the element

4. ProtonProton –Has positive charge –Located in nucleus NeutronNeutron –Has neutral (no) charge –Located in nucleus ElectronElectron –Has a negative charge –Located in electron cloud QuarkQuark –What makes up protons and neutrons, what’s left over Parts of an Atom

5. How an atom looks NucleusNucleus –contains proton & neutron –Is positively charged –Surrounded by electron cloud Electron cloudElectron cloud –Contains electrons –Is negatively charged

6. Changing Atomic Theory DemocritusDemocritus –Atoms make up all substances AristotleAristotle –Matter was uniform throughout, not composed of smaller particles

7. Changing Atomic Theory DaltonDalton –1 st Proved that atoms exist –Model was a simple sphere Electron Cloud ModelElectron Cloud Model –Today’s accepted model –Belief that nucleus (P&N) are surrounded by “cloud” which is the most likely region for the electron to be located in

8. Electron Cloud Model

9. Section 2 Masses of Atoms

10. Composition of Particles within an Atom Particle Mass (g) ChargeLocation Proton 1.6726 x 10 -24 + 1 Nucleus Neutron 1.6749 x 10 -24 0Nucleus Electron 9.1093 x 10 -28 Cloud

11. The Masses of Atoms Atomic NumberAtomic Number –Number of protons in an atom –Allows element to be identified by the number of protons Mass NumberMass Number –Sum of protons and neutrons within an atom # neutrons = Mass # - Atomic #

12. Atomic massAtomic mass –composed mostly of the protons and neutrons in the nucleus Atomic Mass Unit (AMU)Atomic Mass Unit (AMU) –Unit of measurement for atomic particles Proton = 1 AMUProton = 1 AMU Neutron = 1 AMUNeutron = 1 AMU Electron = 1/1836 AMUElectron = 1/1836 AMU

13. IsotopesIsotopes –atoms of the same element with different numbers of neutrons Different isotopes have different properties.Different isotopes have different properties. Name of element followed by mass number identifies the isotope.Name of element followed by mass number identifies the isotope. Average atomic massAverage atomic mass –weighted-average mass of an element’s isotopes –closest to its most abundant isotope. When you round off the Atomic weight, you have the mass # (P + N) for that element’s most common isotopeWhen you round off the Atomic weight, you have the mass # (P + N) for that element’s most common isotope

14. Uranium238.03U92 Atomic Weight Rounded gives the most common isotopes mass # #P + # N Atomic Number #P So, to get the #N, Atomic Weight - Atomic Number (#P + #N) – (#P)= # N

15. Section 3 Structure of the Atom

16. Periodic Table PeriodicPeriodic –repeating according to some pattern Periodic TablePeriodic Table –Arrangement of elements according to some pattern Mendeleev – Father of ChemistryMendeleev – Father of Chemistry –devised the first periodic table based on atomic mass. MoseleyMoseley –arranged the elements by atomic number rather than atomic mass We use his arrangement todayWe use his arrangement today

17. Groups or FamiliesGroups or Families –Vertical columns of elements with similar properties. Elements in the same group have the same number of electrons in their outer energy level.Elements in the same group have the same number of electrons in their outer energy level. PeriodsPeriods –horizontal rows of elements –They contain increasing numbers of protons and electrons.

18. Elements are classifiedElements are classified –Metals (far left on table) –Nonmetals (far right) –metalloids (semimetals) Synthesized elementsSynthesized elements –Man made elements created in laboratories all over the world

19. Orbitals 4 types of orbitals4 types of orbitals S orbital (max of 2 e - ) P orbital (max of 6 e - ) D orbital (max of 10 e - ) F orbital (max of 14 e - )

20. Electron Dot Diagram -------- - - X --------

21. Electron Dot Diagram -------- - - X -------- 1 8 7 6 5 4 3 2

22. 1s 21s 2 2s 2 2p 62s 2 2p 6 3s 2 3p 6 3d 103s 2 3p 6 3d 10 4s 2 4p 6 4d 10 4f 144s 2 4p 6 4d 10 4f 14 5s 2 5p 6 5d 10 5f 145s 2 5p 6 5d 10 5f 14 6s 2 6p 6 6d 106s 2 6p 6 6d 10 7s 2 7p 67s 2 7p 6

23. 1s 21s 2 2s 2 2p 62s 2 2p 6 3s 2 3p 6 3d 103s 2 3p 6 3d 10 4s 2 4p 6 4d 10 4f 144s 2 4p 6 4d 10 4f 14 5s 2 5p 6 5d 10 5f 145s 2 5p 6 5d 10 5f 14 6s 2 6p 6 6d 106s 2 6p 6 6d 10 7s 2 7p 67s 2 7p 6

24. Valence Electrons Electrons in the outermost energy level

25. 1s 21s 2 2s 2 2p 62s 2 2p 6 3s 2 3p 6 3d 103s 2 3p 6 3d 10 4s 2 4p 6 4d 10 4f 144s 2 4p 6 4d 10 4f 14 5s 2 5p 6 5d 10 5f 145s 2 5p 6 5d 10 5f 14 6s 2 6p 6 6d 106s 2 6p 6 6d 10 7s 2 7p 67s 2 7p 6 max 2 max 8 Valence Electrons