7.6 Metals, Nonmetals, and Metalloids By: Monique Briones, Marie Leibfreid, Bryanne Vollmer, Richard Wang

In the Periodic Table No elements exist naturally as individual atoms EXCEPT noble gases Metals—left and middle Nonmetals—top right Metalloids—between metals and nonmetals Hydrogen nonmetal Increase Increase

Characteristic Properties Metals Nonmetals Luster, various colors (silver) Solids malleable and ductile Good conductors heat and electricity Oxides are basic ionic solids Form cations aqueous solution Corrode Dense High melting point No luster, various colors Solids brittle, hard and soft Poor conductors heat and electricity Oxides molecular substances form acidic solutions Anions or oxyanions in aqueous solution Cannot change shape without breaking Low melting point Metallic Character—the extent to which an element exhibits the physical and chemical properties of metals Nonmetallic Character— “the extent…” nonmetals

Metals Solids room temp. (except Hg, Cs 28.4C, Ga 29.8C) Low ionization energies Oxidized Form positive ions easily Noble Gas Electron Configuration (Alkali 1+, Alkaline Earth 2+) Transition metals more than one positive ion Alkali, Alkaline Earth, Transition, and Other

Metals Cont. Compounds with nonmetals are ionic (Ex: oxides) Metal oxides basic, dissolve in water to form metal hydroxides (due to oxide ion) React with acids to form salt and water High melting point

Alkali Group 1A Reactive Do not occur naturally on their own Bond with other elements since there is only one e- in outer shell Soft Explode in water

Alkaline Earth Oxidation number: +2 Reactive Not naturally found uncombined in nature I.E. Beryllium Calcium Radium

Transition Groups 3-12 Valence e- in more than shell Several oxidation states I.E. Titanium Iron Cobalt

Other Metals Groups 13-15 Solid High density Opaque (light cannot get through) Oxidation numbers: +3,+/- 4, -3 I.E. Aluminum Tin Lead

Metal Chemical Reactions Metal + Nonmetal ––––> Ionic substance Ex: 2Ni(s) + O2(g) ––––> 2NiO(s) Metal Oxide + Water ––––> Metal Hydroxide Ex: Na2O(s) + H20(l) ––––> 2NaOH(aq) Ex: CaO(s) + H20(l) ––––> Ca(OH) 2(aq) Basicity Due to Oxide Ion Ex: O2-(aq) + H2O(l) ––––> 2OH-(aq) Metal Oxide + Acid ––––> Salt + Water Ex: NiO(s)+ 2HCl(aq)––––> NiCl2 (aq) + H2O(l)

Nonmetals Vary greatly in appearance 7 Diatomic (Gas: H2, N2, O2, F2, Cl2; Liquid: Br2; Solid: I2) Gain electrons when react with metals to form noble gas electron configuration Completely nonmetal compounds are molecular substances Oxides acidic, dissolve in water to form acids (acid rain) Dissolve in basic solution to form salts

Nonmetal Chemical Reactions Tend to gain electrons when react with metals Ex: 2Al(s) + 3Br2(l) ––––> 2AlBr3(s) Nonmetal Oxide + Water ––––> Acid Ex: CO2(g) + H2O(l) ––––> H2CO3(aq) Ex: P4O10(s) + 6H2O(l) ––––> 4H3PO4(aq) Nonmetal Oxide + Base ––––> Salt + Water Ex: CO2 (g) + 2NaOH(aq) ––––> Na2CO3(aq)+ H20(l)

Metalloids Have metal and nonmetal properties Found in stair shaped section of periodic table Used in computers & calculators Shiny or dull depending on element Shape can be changed easily Ex: Silicon Looks like metal Brittle Poorer conductor of heat and electricity than metal Electrical semiconductors

Additional Research

Chemical Behavior Metals Nonmetals Reducing Agents Form oxides that react with water to give hydroxides Form basic hydroxides React with O, F, H, and other nonmetals, giving ionic compounds React with other metals, giving metallic compounds Lower electronegativities Have 1-5 electrons in valence, usually not more than 3 Low ionization potentials, form cations by loss of electrons Oxidizing agents (except noble gases) Form oxides that react with water to give acids Form acidic hydroxides React with O, F, H, and other nonmetals, giving covalent compounds React with metals, giving ionic compounds Higher electronegativities Usually have 4-8 electrons in valence High electron affinities, form anions by accepting electrons in valence (except noble gases)

Physical Behavior Metals Nonmetals Good conductors of heat and electricity Malleable and ductile in solid state Metallic luster Opaque High density Mostly solids Crystal structure in which each atom surrounded by 8-12 nearest neighbors (metallic bonds between atoms) Poor conductors Brittle and nonductile in solid state Show no metallic luster May be transparent or translucent Low density Gases, liquids, or solids Form molecules that consist of atoms covalently bonded; noble gases monatomic

Metalloids Has both properties Has appearance of metal, but behaves chemically like nonmetal Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te), Polonium (Po), Astatine (At) Not Aluminum Semiconductors of electricity Conductivity increases with temp. (metals decrease) Ex: Silicon Metallic luster Forms weak acid

Periodic Trends Consistent with trends of ionization energy, electron affinity, and electronegativity Effective nuclear charge increase across period (left to right) and decrease down group (top to bottom) Atomic Radius (decrease) Ionization Energy (increase) Electron affinity (general increase) Electronegativity (increase) Polarizability (Decrease)

Dependence Oxidation Number As oxidation number of element increases, metallic behavior decreases, nonmetallic behavior increases HOCl (+1) is weak acid, HClO4 (+7) is strong acid TlCl (+1) is ionic, TlCl3 (+3) is covalent

Acidic and Basic Properties Basic oxide—oxide that reacts with acids Acidic oxide—oxide that reacts with bases Amphoteric oxide—oxide with both basic and acidic properties MgO(s)+ 2HCl(aq) ––––> MgCl2 (aq) + H2O(l) CO2 (g) + NaOH(aq) ––––> NaHCO3(aq) Al2O3(s) + 6HCl(aq) ––––> 2AlCl3(aq) + 3H20(l) Al2O3(s) + 2NaOH(aq) ––––> 2Na[Al(OH)4](aq)

Helpful Websites: http://www.gordonengland.co.uk/elements/non%20metals.htm http://www.cstephenmurray.com/onlinequizes/chemistry/readingperiodictable/metalnonmetal.htm *** http://www.mikeblaber.org/oldwine/chm1045/notes/Periodic/Metals/Period06.htm http://www.webelements.com/