Elements and the Periodic Table

1. Elements and the Periodic Table State Standard: Each of the more than 100 elements of matter has distinct properties and atomic structure.

2. How is the Periodic Table organized? What is the structure of an atom? Can you identify the different regions of the Periodic Table? How are the number of protons and neutrons of an atom/element determined? What are some properties by which elements can be classified? *Distinguish between the variable and controlled parameters of a test?

3. What is an atom? • Smallest particle of element • Nucleus • Protons (+) • neutrons (neutral) • Mass of atom (amu) • Electrons (-) • Valence energy level • Outer most e-

4. What is an isotope? Atoms with same number of protons Atoms have different mass number Number of neutrons changes

5. How do I find the # of neutrons? • Atomic mass unit (amu) • Find the amu and subtract the atomic number. • Difference= number of neutrons

6. Organization of Periodic Table • Arranged by increasing mass • Arranged by atomic number • Groups columns/vertical • Same valence e- # • Increasing mass • Similar properties • Periods= rows/horizontal • Most reactive on L • Least reactive on R • Transitions from metals >nonmetals • Mendeleev 's Completed Periodic Table

7. Element Square Chemical symbol Chemical name Atomic number number of protons in atom Atomic Mass Average mass of all isotopes of atom AMU

8. Properties of Metals • Slinky • Physical: • Conduct electricity & heat • Thermal conductivity • Electrical conductivity • luster = shiny • Density= mass ÷ volume • Malleable= • made into shapes • made into thin sheets • Ductile= pulled into wire

9. Properties of Metals cont. Chemical: reactivity- speed & efficiency of rxn Spectacular + quick Corrosion- slow wearing away

10. Identify the regions of The Periodic Table!

11. Alkali • Group 1 • Highly reactive • Lose electron • Always found as compounds • Can be separated in lab • pure substance=shiny • Most important • Na, K • Li used in batteries & medicine • Food contains • Na, K

12. Alkali-earth Metals • Group 2 • Fairly hard • Grayish white • Good conductor electricity • Lose 2 e- • Most common: Mg, Ca • Ca= teeth, bones • Mg= hard metal, mixed w/ Al to make light wt. material

13. Transition Metals • Groups 3-12 • Hard and shiny • Good conductors of electricity • Less reactive • Never found pure in nature • Fe found in hemoglobin for blood

14. Metals in mixed groups • Group 13-15 • Found as compounds in nature • Most familiar: Al, Sn, Pb

15. Lanthanides • Top bubble/pull out row • Mixed w/ common metals to create alloys • Metal mixed w/ at least one other element (metal) • Found as compounds • Sc & Y similar traits • May be produced for strong magnets • Rare earth metals

16. Actinides • Below Lanthanides • Naturally occur… • Ac, Th, Pa, U • Laboratory made • All others unstable • Last only fraction of second • Quickly break into stable forms

17. Futuristic Actinide Products

18. Synthetic Elements • Elements with atomic numbers > 92 • Engineered in laboratory setting • Force neutrons into existing nuclei • Use of particle accelerator • New elements parallel new particle accelerators

19. Nonmetals • Chemical properties • Gain or share e- • Metal react with nonmetal, e- moves to nonmetals • NaCl • (ionic bond) • Rust • (metal ionized) • New substance

20. Nonmetals • Physical Properties • Poor conductor of heat and electricity • As solid, dull and brittle • 4 are gases at room temperature • N, O, Fl, Cl

21. Inert Gases • Group 18 • aka Noble gas • Full valence electrons • 8 valence electrons • Exist in Earth’s atmosphere • Small amounts • Un-reactive • Laboratory synthesize compounds • Uses… • Neon signs • Balloon gas

22. Halogens • Group 17 • Very reactive • Pure substance is dangerous • Gains e- • Compounds are useful • Uses… • Strengthen teeth • Melt ice or snow • Non-stick coating • Salt • Photographic film

23. Chalcogens or Oxygen family • Group 16 • highly reactive • 3 nonmetals • 2 semi-metals • Oxygen = • Diatomic molecule • O2 • triatomic molecule • O3 • Oxygen most abundant in Earth’s lithosphere • H2SO4 used in manufacturing

24. Nitrogen or Pnictogens • Group 15 • Two nonmetals • P • Used in matches • reactive • N • Found in nature as diatomic or N2 • Found in air, fertilizers, nutrient • Nitrogen most abundant in atmosphere • Two semimetals • As or Sb • Poison or carcinogen • One metal • Bi • Uses: medicine, fire detection, cosmetics, replaces Pb in shells

25. Semimetals • Properties of metals and nonmetals • Solid at room T • Brittle, hard, slow to react • Uses… • Computer chips • transistors • lasers • Vary in ability to conduct electricity • Dependent on • Temp., exposure to light, presence of impurities

26. Hydrogen • Simplest atom • Three isotopes • No family/group • 90% of universe • 1% of lithosphere, oceans, atmosphere • Found mostly as compound (water)

27. Radioactive Decay • Produces particles • Alpha, beta, gamma • Move fast • Stopped by collisions with atoms • Alpha , paper • Beta, aluminum • Gamma, thick lead or concrete • Injure skin • Uses • Industrial, medicine diagnose/treatment

28. Radioactive Decay cont. • Radioactive Decay • Filtration of radioactive particles

29. Any questions?