The Periodic Table of Elements

1. The Periodic Table of Elements

2. Periodic  Periodic Law  Periodic Table • Something periodic occurs at regular or predictable intervals • Periodic law - physical and chemical properties of the elements are periodic functions of their atomic numbers • Periodic Table of Elements – arranged by atomic number - shows patterns in properties

3. Element • A pure substance made up of one kind of atom that cannot be broken down into simpler substances • 90 occur naturally on earth • 25 were synthesized (made) by scientists

4. Dmitri Mendeleev • 1860’s • Grouped elements together according to their atomic masses and similarities Image taken from: http://jscms.jrn.columbia.edu/cns/2006-04-18/fido-luxuriantflowinghair/mendeleev/

5. Mendeleev’s Published Periodic Table of Elements Why do you think there are question marks here? Image taken from: http://www.chemsoc.org/networks/learnnet/periodictable/post16/develop/mendeleev.htm

6. Mendeleev’s Predictions • Mendeleev’s Table had missing elements or “gaps,” BUT he was able to predict the characteristics of these missing elements because of Periodic Law. GermaniumActual “Ekasilicon” Prediction Notice how Mendeleev’s predictions (orange column) were very accurate when compared to Germanium’s actual characteristics (green column)

7. Henry Moseley • 1914 • Rearranged the elements by their atomic numbers • He concluded that the number of protons in an atom is its atomic number Image taken from: http://dewey.library.upenn.edu/sceti/smith/

8. 3 Classes of Elements Using this as a guide, color code your periodic table to show the three classes. Start by highlighting the “zig-zag.”

9. Metals Location • Left of the zigzag line (exception  Hydrogen) Chemical Properties • Have few electrons in their outer energy level, thus lose electrons easilyMakes CATIONS Ca2+ #P > #e- Positive Charge Physical Properties • ductile, good conductors, malleable, shiny, most are solid @ room temperature Image taken from: http://chemistry.about.com/od/periodictableelements/ig/Element-Photo-Gallery.--98/Sodium.htm What metal is not a solid @ room temperature?

10. - + + - - + + + + + - - - - + - - + + + + + - - + + - - - - Atoms with Few Electrons in their Outer Energy Level Notice: only 1 electron in outer level Notice: only 2 electrons in outer level

11. Non-Metals Location • Right of the zigzag line Chemical Properties • Almost full, or totally full outer energy levels. • Tend to gain electrons Makes ANIONS O2- #P < #e- Negative Charge Physical Properties • not ductile or malleable, not shiny, poor conductors, most are solid, but some are gas at room temperature Image taken from: http://nobel.scas.bcit.ca/resource/ptable/cl.htm Image taken from: https://www.dmr.nd.gov/ndgs/rockandmineral/sulfur.asp

12. - + + + + - - - - - - + + + + - - + + + + + + + - + + - - + + - - - - - - - Atoms with Full or Almost Full Outer Energy Level Notice: 2 electrons in outer level – FULL Notice: 6 electrons in outer level – almost full Notice: 7 electrons in outer level – almost full

13. Metalloids Location • Border the zigzag line Chemical Properties • Most atoms have ~½ full set of electrons in outer levelMake anions or cations Physical Properties • have properties of both metals and non-metals Image taken from: http://library.thinkquest.org/C0113863/bios.shtml Image taken from: http://library.thinkquest.org/C0113863/bios.shtml

14. - - - + - - - - + + + + + + + - + + + + + - + - - - - + + + + + - - - - - - Atoms with ~½ Complete Outer Energy Level Notice: only 4 electrons in outer level Notice: only 3 electrons in outer level

15. Important Features of the Periodic Table:Period (Row) • each horizontal row of elements on the periodic table How many periods (rows) are on the Periodic Table Of Elements? FROM LEFT TO RIGHT OR RIGHT TO LEFT

16. Period Properties • Seven periods (numbered from the top down) • Atomic #’s and masses increase as you move from the left to the right in a period • All elements in the same period have the same number of energy levels • Period 1 = 1 energy level • Period 2 = 2 energy levels • Period 3 = 3 energy levels • Etc…

17. - - - + + + + - - - - - + - - + + + + + + + + + + + + + + - + - - - - - - - + + + - + + + - + - + + + - - - + + + - + + - - - - + + - - - - - - - - Examples of Period elements having the same number of energy levels in their atoms In what period do you think these atoms reside? In what period (row) do you think these atoms reside?

18. Important Features of the Periodic Table: Group (Family) • each column of elements on the periodic table How many groups (families) are on the Periodic Table Of Elements? FROM TOP TO BOTTOM OR BOTTOM TO THE TOP

19. Group (Family) Properties • Eighteen groups (numbered from left to right) • Atomic # and masses increase as you move from the top down in a group (family) • Atoms of elements in the same group have the same number of valence electrons Exceptions: Transition elements (3-12) • Elements in groups usually have similar physical and chemical properties BECAUSE THEY HAVE THE SAME NUMBER OF VALENCE ELECTRONS

20. 1 H 1.008 3 Li 6.941 + 11 Na 22.990 + + - 19 K 39.098 - - + 37 Rb 85.468 - - + + + + 55 Cs 132.905 + - - + + 87 Fr (223) - - - - Examples of Group Elements with the same # of valence electrons How many electrons do each of these atoms have in their outer orbital/level? What group (family) do these elements reside in?

21. Identify the Element Period 2 – Group 14  Period 5 – Group 2  Group 17 – Period 6  Group 4 – Period 7  Rutherfordium - Rf Carbon - C Strontium - Sr Astatine - At