Bonds Ionic Bond formed due to a difference

Bonds Ionic – • Bond formed due to a difference in charge – Loss or gain of an electron • Usually forms between a metal and a nonmetal

Bonds Covalent – • Bond formed from two atoms sharing an electron • Commonly found in “organic” compounds (with H, C, and O, among others)

Dmitri Mendeleev • Order elements by atomic mass 1834 - 1907 • Periodic Law – When the elements are arranged in order of increasing relative mass, certain sets of properties recur periodically • used pattern to predict properties of undiscovered elements

Periodic Table Pattern nm H 2 O a/b H 1 H 2 m Li 2 O m/nm Be. Onm B 2 O 3 nm CO 2 nm N 2 O 5 nm O 2 nm OF 2 Li b Be a/b B a C a N a O F 7 Li. H 9 Be. H 2 11 ( BH 3)n 12 CH 4 14 NH 3 16 H 2 O 19 HF left right across a row (period) increasing atomic mass (not relative mass); organized based on their activity and properties

Periodic Table Pattern nm H 2 O a/b H 1 H 2 m Li 2 O m/nm Be. Onm B 2 O 3 nm CO 2 nm N 2 O 5 nm O 2 nm OF 2 Li b Be a/b B a C a N a O F 7 Li. H 9 Be. H 2 11 ( BH 3)n 12 CH 4 14 NH 3 16 H 2 O 19 HF m Na 2 O m Mg. O m Al 2 O 3 nm/m Si. O 2 nm P 4 O 10 nm SO 3 nm Cl 2 O 7 S a Cl a Na b Mg b Al a/b Si a P a 23 Na. H 24 Mg. H 2 27 (Al. H 3) 28 Si. H 4 31 PH 3 32 H 2 S 35. 5 HCl up down column; similar properties; how the elements react with H and O • some gaps were left in table for undiscovered elements; properties of these elements were predicted.

PERIODIC TABLE Non-metals Metalloids 7

PROPERTIES OF METALS & NON-METALS Metals Non-metals • Mostly solid • Can be solid, liquid or gas • Have shiny appearance • Have dull appearance • Good conductors of heat & electricity • Poor conductors of heat & electricity • Malleable & ductile • Brittle (if solid) • Lose electrons • Gain or share electrons 8

Metals Non-metals

METALLOIDS q Metalloids are elements that possess some properties of metals and some of non-metals. q The most important metalloids are silicon (Si) and germanium (Ge) which are used extensively in computer chips. 10

Metalloids Properties of Silicon shiny conducts electricity brittle

PERIODIC TABLE Metallic character decreases increases going down acrossaagroup period. Least metallic Most metallic elements F Cs Fr 12

PERIODIC TABLE q Seven elements exist as diatomic molecules. q All others exist as monatomic (single atom). 13

PERIODS & GROUPS q q The Elements periodic in the table same is composed family have of periods similar (rows) properties, and areorcommonly referred to by their traditional groups families (columns). names. 14

PERIODS & GROUPS q Group The group Elements Alkali Noble Halogens gases metals 2 elements in are ofare groups metals the areun-reactive most soft are 1 -2 inmetals called reactive between and 13 -18 gases alkaline-earth that nonmetals, the are that are main very referred aregroup commonly reactive. and metals. to occur as main-group They used in These elements nature in often metals light are only react or bulbs. called are as representative explosively compounds. less transition reactivewith metals. than groups. other alkali elements. metals. 15

Pick a group • Alkali metals • Alkaline earth metals • Transition Metals • Metalloids • Halogens • Noble Gasses • Name of Group • Elements in the group • Properties of the elements in the group • Bonds usually formed • Reaction to fire