2 3.1 ElementsElement- A pure substance that cannot be separated into simpler substances by chemical or physical means.Pure Substance- A substance in which there is only one type of particles
3 Properties of Elements Each element has its own characteristic properties.These include boiling/melting point, density, reactivity, flammability, etc.An element may share one or two properties with another element, but it will not share all its properties with another element. There will be specific properties for each element.
4 Classifying Elements You can use properties to identify elements. Think about how many types of dogs there are.How do you tell one breed from another?Categories of ElementsMetalsNonmetalsMetalloids
5 Classifying ElementsMetal- an element that is shiny and conducts heat and electricity wellPropertiesMalleable – ability to be hammeredinto sheetsDuctile – ability to be drawn intowires
6 Classifying Elements 1.some are shiny Nonmetal – an element that conducts heat and electric poorlyProperties1. dull2. brittle – not malleableMetalloid- an element that has properties of metals and nonmetals1.some are shiny2. some are dull3. somewhat malleable and ductile4. some are good conductors of heat and electricity5. some are poor conductors of heat and electricity
8 Classifying Elements Appearance Conductivity Physically Example Metal AppearanceConductivityPhysicallyExampleMetal ShinyGoodmalleable., ductileLead, CopperNonmetal DullPoorBrittleSulfur, oxygenMetalloidSome Shiny/ some dullSome good/ some poorSomewhat malleable and ductileSilicon, boron
9 3.2 CompoundsCompound- a substance made up of atoms of two or more different elements joined by chemical bondsExamples: H2O (water), NaCl (table salt)A particle of a compound is called a moleculeElements do not randomly combine. They join into a specific ratios according to their masses.
10 Properties of Compounds Each compound has its own physical properties and chemical properties.The properties of a compound are different from the properties of the elements that form it.Sodium Chlorine Table SaltExplosive soft metal Yellow Piousness Gas
11 Breaking Down Compounds Some compounds can be broken down into their elements or simpler compounds by chemical means.Sometimes energy in the form of heat is needed to do this.
12 3.3 MixturesMixture- A combination of two or more substances that are not chemically combined.An example would be a salad (or salsa as in the picture). The cheese, sauce, and dough are still the same items after you make the pizza.
13 Properties of Mixtures Sometimes you cannot see all the components like in salt water This is called a homogeneous mixture. It includes salt and water.Since mixtures are not chemically combined, you can separate the different substances by physical methods.Components in a mixture do not need to be in a specific ratio.
14 Separating MixturesSometimes you can just pick ingredients out of a mixture (pizza)Other ways to separate mixtures include:evaporation – separates a mixture based on boiling points Ex: salt in watermagnet – anything ferromagnetic will stick to the magnet EX. Iron & Aluminum nails in boxdistillation – separates a mixture based on density. Ex: crude oil – gasoline & propanecentrifuge – separates based on particle sizeEx: blood
15 Compounds vs. mixtures Mixtures Compounds Made of elements, compounds or bothMade of elementsNo change in original properties of componentsChange in original properties of componentsSeparated by physical meansSeparated by chemical meansFormed by using any ratio of componentsFormed using a set ratio of components
18 Solutions Solution- A mixture that appears to be a single substance. Particles are small & cannot be filteredSolutions have the same composition throughout.Example: Salt WaterSolute- Substance that is dissolved. (Salt)Solvent- The substance in which the solute is dissolved. (water)
19 Solutions ContinuedThe term soluble means able to dissolve. Insoluble means unable to dissolve.Solutions can be solids, liquids, or gases.Solubility- Measure of the amount of solute dissolved in a solvent.This is expressed as g/mLTo increase solubility:heatstircrush – smaller particles
20 ColloidsColloid A type of mixture in which the particles are dispersed throughout but are not heavy enough to settle outParticle size is larger than that of a solution but small enough they will still pass through a filter.Examples of colloids: milk, fog
21 ColloidsColloids scatter light. (fog) You can actually see the beam of light in the colloid.
22 SuspensionsSuspensions- A mixture in which the particles of a material are dispersed throughout a liquid or gas but are large enough that they settle out.Particles are large enough to settle out.Suspensions can be separated by passing through a filter.Examples: Italian salad dressing, muddy water
23 Elements, Compounds, Mixtures ElementsCompoundsMixturesHow many parts make it up? 1 2 or more 2 or more elements or compoundsPure: more than one substance? pure Not pureChemically or physically combined? N/A ChemicallyphysicallyChemical change to make them? YesnoFixed ratio?YesHow separated: chemically/physically?Chemically
24 Solution, suspension, colliod ElementsCompoundsMixturesHow many parts make it up? 1 2 or more 2 or more elements or compoundsPure: more than one substance? pure Not pureChemically or physically combined? N/A ChemicallyphysicallyChemical change to make them? YesnoFixed ratio?YesHow separated: chemically/physically?Chemically