1. (almost 2,000)

2. # ofprotons inatomsnucleusused toidentify Atomic mass numberelement sum of protons & neutrons 3. isotope-elementwith same #of protons &different #of neutrons 4. Pre-Periodic Table Chemistry was a mess!!! No organization of elements. Imagine going to a grocerystore with no organization!! Difficult to find information. Chemistry didnt make sense. 5. Dmitri Mendeleev: Father of the TableHOW HIS WORKEDSOME PROBLEMS Put elements in rows He left blank spacesby increasing atomic for what he said were undiscoveredmass.elements. (Turned Put elements inout he was right!)columns by the way He broke the patternthey reacted.of increasing atomic weight to keep similar reacting elements together. 6. Each square of periodic tableincludes: elements atomic number= # of protons in its nucleus chemical symbol name atomic mass= avg. mass of all isotopes of that element 15.9994 7. Chemical symbol 1 or 2 letters ex: iron= Fe 8. Periods Horizontal rows 7 periods 9. Groups columns aka families 18 groups eg: Group 15= nitrogen family each group has similar characteristics 10. physical properties of a metal hardness shininess malleable=can be pounded into shapes ductile=can be pulled out into a long wire conductor - can transmit heat & electricity magnetic most are solids at room temp. (except ___________ ) mercury 11. chemical properties of a metalreactivity __________= ease & speed at which anelement combines or reacts with otherelements some - very reactive (ie. sodium) others - unreactive (ie. gold) 12. reactivity ease & speed at which an __________= element combines or reacts with other elements some - very reactive (ie. sodium) 13. corrosion process of reaction &wearing away ie. iron rusting 14. alloy mixture of metals ie. copper + tin= bronze 15. Group 1- alkali metals from Li Fr (not H) very, very reactivePotassium reacting with water have 1 valence electron Lithium reacting with water 16. Group 2- alkaline earth metals 2nd column Be Ra very reactive- never alone lose 2 valence electrons most common- Ca & Mg 17. Groups 3-12 - transition metals bridge between very reactive metals &less reactive metals ex: Fe, Ag, Pt 18. Groups 13-16 incl metals, nonmetals & metalloids ex. Al, Sn, Pb 19. lanthanides & actinides- rare earth elements found @ bottom of periodic table fit in periods 6 & 7 placed at bottom for convenience 20. Neodymium, one of the lanthanide elements, isused in manufacturing the tiny speakers insidestereo headphones. 21. Curium, one of the actinide elements,is used as a source of high-energy particles that heat and provide power for certain scientific equipment aboard the Mars Exploration Rover. 22. synthetic elements elements w/ atomic # > 92 not found naturally on Earth made when nuclear particles collide 23. particle accelerators make elements above atomic #95 move atomic nuclei until reach very highspeeds 24. Element 110-118, elements withthree-letter symbols, have beengiven temporary names and symbols. In the future, scientists around theworld will agree on permanentnames and symbols for theseelements. 25. Nonmetal Element that lacks mostproperties of metalsdull- not shinybrittle- not malleablepoor conductors 26. Nonmetals Located at right of zigzag line onperiodic table 10/16 = gases Most form compounds, exceptGroup 18 27. Boron Family Group 13 28. Carbon Family Group 14 C (nonmetal) Pb 4 valence electrons 29. Carbon Family Contains elementsimportant to life &computers Carbon = basis for entirebranch of chemistry silicon & germanium-important semiconductors 30. Nitrogen Family Group 15 N Bi 2 nonmetals- N & P 5 valence electrons 31. Group 15Nitrogen Family Nitrogen makes up over of the atmosphere. Nitrogen andphosphorus are bothimportant in livingthings. Most of the worldsnitrogen is not availableto living things. The red stuff on the tipof matches isphosphorus. 32. Oxygen Family Group 16 O Po 3 nonmetals- O, S, Se 6 valence electrons 33. Diatomic molecules Compounds of 2 identicalatoms 34. Halogen Family Group 17 F At 7 valence electrons very reactive typically gains or shares 1electron 35. Halogens Group 17 Very reactive, volatile,diatomic, nonmetals Always foundcombined with otherelement in nature Used as disinfectants& to strengthen teeth 36. Noble Gasesgroup 18He Rn8 valence electronsvery stable & unreactivedo not form compounds b/c do not gain,lose, or share valence electrons 37. The Noble Gases Group 18 VERY unreactive,monatomic gases Used in lighted neonsigns Have a full valenceshell. 38. Hydrogen alone in upper corner not grouped in a family very diff. properties has 1 proton & 1 electron some have neutrons 39. Metalloids on borderbetween metals &nonmetals 8 metalloids characteristics ofboth metals &nonmetals 40. Metalloids most useful property= varyingability to conduct electricityused to make semiconductors= can conduct electricity under certain conditions 41. Review1. What can you predict from an elements location in the periodic table?2. To make most synthetic elements, scientists use powerful machines called ___________.3. Which group contains the most elements?4. What prediction did Mendeleev make that came true less than 20 years later?5. Fluorine, chlorine, bromine, and iodine are part of what family? 42. Bo