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TOPIC: Metals vs Nonmetals. Classifying the Elements. 2/3 (75%) of elements are metals Remaining elements: non-metals & metalloids (semi-metals) Metalloids: some properties of metals & some properties of nonmetals Staircase: dividing line between metals & nonmetals
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Classifying the Elements • 2/3 (75%) of elements are metals • Remaining elements: non-metals & metalloids (semi-metals) • Metalloids: • some properties of metals & some properties of nonmetals • Staircase: • dividing line between metals & nonmetals • elements to left are metals (except H) • elements to right are non-metals
Most elements are solid at room temperature • Some nonmetals are gases • All the noble gases, of course • Some diatomics (H2 N2 O2 F2 Cl2) • There are only 2 Liquids at STP (room temp) • Br2(non-metal) and Hg (metal)
Properties of Metals • Malleable – flattened into sheets • Ductile – drawn into wires & tubes • have Luster • Good Conductors of heat & electricity • Solid at room temperature (except Hg) • Metals lose electrons & form positive ions “Metals are losers” • Most reactive metal is Fr • Most reactive family is Alkali Metals
So…metals don’t want electrons, they want to get rid of them
Metals also have… • Low electronegativity (low attraction for electrons) • Low ionization energy (doesn’t take a lot of energy to remove an electron)
Properties of Nonmetals • generally gases or solids (except Br2) • solids are Brittle • solids are Dull • poor conductors of heat & electricity • Nonmetalsgain electrons & form negative ions “Nonmetals are winners” • Most reactive nonmetal is F • Properties: OPPOSITE of metals
Nonmetals also have… • high electronegativity (high attraction for electrons) • high ionization energy (takes a lot of energy to remove an electron)
Increased Electronegativity Increased Ionization energy
Properties of Metalloids 7 metalloids: • 5 on right of staircase: B,Si,As,Te,At • 2 on left of staircase: Ge,Sb Each metalloid has some metallic and some nonmetallic properties • Example:Si • shiny like metal but brittle like nonmetal Metalloids are elements touching the stairs (except Al) and have some properties of metals and some of nonmetals
previous | index | next Cs has more energy levels, so it’s bigger Li: Group 1 Period 2 Cs: Group 1 Period 6
previous | index | next How about as you go across?!
previous | index | next as go across row size tends to decrease a bit because of greater PPP “proton pulling power”