+ Chapter 7 The Periodic Table Chapter 7

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+ Organizing the Elements Prior to 1860 There were 63 known elements No know pattern had been determined Although new elements might be accidentally discovered from time to time, it was generally believed that all of the elements had been discovered

+ Who Invented It??? Dmitri Mendeleev (1860’s) Found a pattern. When organized by atomic mass Properties were periodic (repeating pattern) Elements could be predicted However, a few elements did not fit...

+ Who Invented It??? Henry Moseley (1914) If the elements are arranged by atomic number they fit! Our periodic table is arranged by atomic number.

+ Periodic Law  As more and more elements have been discovered each new element has supported periodic law  “Chemical and physical properties of elements are periodic functions of their atomic numbers.”  C & P properties repeat and can be predicted!

+ Groups (families) From top to bottom, or column Elements in a family have similar physical properties Periods From left to right, or row Elements follow a repeating pattern (periodicity) as you go from left to right, each element changing its reactivity and other properties based on this pattern 29 Cu 47 Ag 79 Au Gold, silver and copper share similar properties and belong in the same group LiBeBCNOFNe NaMgAlSiPSClAr He H _ _ _

+ Group 1- Alkali Metals Group 2- Alkaline Earth Metals Groups3-12- Transition Metals Group 17- Halogens Group 18- Noble Gases

+ Three Classes of Elements Metals Left side of the table Shiny, malleable, ductile, conduct heat and electricity Nonmetals right side of the table Dull, brittle, poor conductors Metalloids Either side of zigzag line (there are six of them) Have some of the properties of metals, but not all, properties can change under certain conditions (semi- conductors) Metals lithium, calcium, iron, gold, aluminium Nonmetals carbon, oxygen, helium, neon Metalloids boron, silicon, germanium, arsenic, antimony, tellurium

+ Also called… _______________ Groups of the Periodic Table Alkali Metals Alkaline Earth Metals Transition Metals Lanthanides Actinides Halogens Noble Gases H Metals Metalloids Nonmetals Rare-Earth Metals B Si GeAs SbTe

+ Group 1: Alkali Metals Metals Only 1 electron in their outer level Very Reactive-will easily give up their electron Soft, silver colored, shiny, low density Examples: Li, Na, K, Rb, Cs, Fr

+ Group 2: Alkaline Earth Metals  Metals  2 electrons in outer level  Very Reactive, but less reactive than Group 1 (have 2 electrons to give up)  Silver colored, more dense than Group 1  Examples: Be, Mg, Ca, Sr, Ba, Ra

+ Groups 3-12: Transition Metals  Metals  1 or 2 electrons in outer level  Reactive, but less reactive than Group 1 or Group 2  Shiny, good conductors of heat and electricity, more dense than Group 1 or Group 2  Examples: Ni, Cu, Pt, U

+ Lanthanides and Actinides Transition Metals in Periods 6 and 7 Moved to the bottom to make room. Lanthanides follow lanthanum (La) Actinides follow actinium (Ac)

+ Group 13: Boron Group 1 Metalloid / 4 Metals 3 electrons in outer level Reactive Solid at room temperature Examples: B, Al, Ga, In, Tl

+ Group 14: Carbon Group 1 Nonmetal / 2 Metalloids / 2 Metals 4 electrons in outer level Reactivity varies Solid at room temperature Examples: C, Si, Ge, Sn, Pb

+ Group 15: Nitrogen Group 2 Nonmetals / 2 Metalloids / 1 Metals 5 electrons in outer level Reactivity varies All but Nitrogen (N) solid at room temperature Examples: N, P, As, Sb, Bi

+ Group 16: Oxygen Group 3 Nonmetas / 1 Metalloid / 1 Metal 6 electrons in outer level Reactive (trying to get a full shell) All but oxygen (O) are solid at room temperature Examples: O, S, Se, Te, Po

+ Group 17: Halogens  All Nonmetals  7 electrons in outer level  VERY Reactive  Bad conductors of heat and electricity  React violently with Alkali Metals (Group 1) to make “salts” such as NaCl  Never found alone in nature, always as a “salt”  Examples: F, Cl, Br, I, At

+ Group 18: Noble Gases All Nonmetals 8 electrons in outer level (2 for Helium) Not Reactive Colorless, odorless gases Used in light bulbs (Argon, Xenon, Neon, Helium) Examples: He, Ne, Ar, Kr, Xe, Rn

+ Hydrogen: Its Own Group  Part of Group 1, but unique.  Nonmetal  1 electron in outer level  Reactive (easily gives up electron)  Colorless, odorless gas at room temp.  Reacts explosively with oxygen.  Used in rocket fuel.  Most common element in the universe  Hydrogen atoms cause acidity

+ Alkaline Earth Metals Transition Metals Halogens Noble Gases H Alkali Metals Lanthanides Actinides Alkaline Earth Metals Halogens