Presentation on theme: "Section 4: Nonmetals and Metalloids"— Presentation transcript:
1 Section 4: Nonmetals and Metalloids Objectives:locate nonmetals and metalloids in the periodic tablecompare the physical and chemical properties of nonmetals with those of metals, and describe the properties of metalloids
2 What is a Nonmetal? The element on the right side of the zigzag line are nonmetals.(yellow boxes)•An element that does not have most of the properties of metal.
3 Physical Properties of Nonmetals •low melting point-many are gases at room temperature
4 Few are solids at room temperature Examples: Sulfur, carbon, and iodineOnly bromine is a liquid at room temperature.Most physical properties of nonmetals are opposite of the metals;-dull, not shiny-solid nonmetals are brittle (not malleable and not ductile)-poor conductors of heat and electricity.
5 Chemical Properties of Nonmetals Except for Group 18 most form compounds-able to gain or share electrons(usually do not loose electrons)-Group 18 has full valence shellsdo not easily loose or share electrons
6 Compound of Nonmetals Nonmetals usually react with metals Valence electrons move from the metal atoms to the nonmetalsExample: table salt (NaCl)sodium has 1 valence electron and chlorine has 7Nonmetals can form compounds withother nonmetalsforms diatomic moleculessuch as oxygen and hydrogen
7 Families of Nonmetals Carbon is most important in chemistry of living things·All living thingmade up ofcarbon.Carbon only nonmetal is this familySilicon and germanium are metalloidsTin and lead are metalContain 4 valence electron
8 Diamonds and soot are both forms of carbon.Diamonds are the hardest materialmaterials. It is used as a jeweland for saws, drills, and files.Soot is very soft. It is used as pigmentin paints and crayons
9 Nitrogen Group Contain 5 valence electrons 80% of atmosphere is nitrogenMost living things get nitrogen from food eatenSome bacteria use nitrogen from the air
10 Phosphorus is in nitrogen group Not stable as elementMust combine with other elements to form compounds
11 Oxygen Group Elements in this group share or gain 2 Electrons Group contains 3 nonmetalsImportant gas for all living thingsOxygen is most abundant element isEarth crust and 2nd most abundant element in earths atmosphere
12 Sulfur is nonmetal in oxygen family Used in production of rubber bands, tires, and medicines
13 Halogen Family All elements have 7 electron Usually gains or shares one electronAll elements are nonmetalsVery reactiveDangerous to humans in pure form
14 Halogens Fluorine used in nonstick cookware and fluoridation of water tofight tooth decayChlorine is used as disinfectantfound in table saltBromine is used in compound of silver bromide that is used in photographic film.Iodine is used as disinfectant
15 Noble Gases Valence shell is full with 8 electrons Very stable and unreactiveAll are found in earth’s atmosphere insmall amounts
17 Hydrogen Stands Apart 1 proton and 1 electron however chemical propertiesare so different it is notgrouped into a family90% of atoms in universe arehydrogen, but only 1% ofmass of crust, oceans, andatmosphere is hydrogenRarely found on earth as pureelement
18 Metalloids Areas shaded in green are metalloids Have some characteristics ofmetals and some of nonmetals
19 Most useful property of metalloid is ability to conductelectricitySilicon and germaniumare used to makesemiconductorSemiconductors carry electricityunder some conditions andduring other conditionscannot carry electricityUsed in computer chips, transistors,and lasers.