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Reporting Category 1:  Matter and the Periodic Table

Reporting Category 1:  Matter and the Periodic Table. 12 STAAR questions TEKS 4-5 *Indicate Readiness TEKS. *4A  Differentiate between physical and chemical changes and properties.

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Reporting Category 1:  Matter and the Periodic Table

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  1. Reporting Category 1:  Matter and the Periodic Table 12 STAAR questions TEKS 4-5 *Indicate Readiness TEKS

  2. *4A Differentiate between physical and chemical changes and properties.  Physical Properties of MatterDefinition: a property that can be observed without changing the identity of the substance.Chemical PropertiesDefinition: a property that can be observed only during a chemical change

  3. Changes of Matter Physical Change  change in the form or state of a substance, for instance, from solid to liquid or liquid to gas or solid to gas, without changing the chemical composition of the substance. As we will see later, chemical bonds are not broken in a physical change.Examples:Boiling of water and the melting of ice. Chemical Change  The change of a substance into another substance, by reorganization of the atoms, i.e. by the making and breaking of chemical bonds. In a chemical change chemical reaction takes place. The substance changes into a new substance by rearranging the number and kinds of atoms.Examples: Rusting of iron and the decomposition of water, induced by an electric current, gaseous hydrogen and gaseous oxygen. Recognizing a chemical change (rules of thumb):1. formation of a precipitate2. change in color3. effervescence (production of a gas)4. change in energy (temperature)5. change in smell

  4. Mixture Mixture: two or more substances, combined in varying proportions - each retaining its own specific properties. The components of a mixture can be separated by physical means, i.e. without the making and breaking of chemical bonds. Examples: Air, table salt thoroughly dissolved in water, milk, wood, and concrete. CHARACTERISTICS: *percentage composition varies from sample to sample * components are chemically different and retain properties in a mixture *do not melt/boil at a definite temperature Homogeneous mixture Heterogeneous mixture components uniformly mixed - also called solutions heterogeneous mixtures components not uniformly mixed

  5. 4B: Extensive and Intensive Properties • Extensive properties physical property that depends on the amount of matter present or a • property that changes when the size of the sample changes. Not very useful in identifying unknown substances • examples: mass, volume, length • Intensive properties physical property that does not depend on the amount of matter present or doesn't change when you take away some of the sample. Can be very useful in identifying unknown substances • examples: density, boiling point, conductivity

  6. 4C States of Matter GAS • assumes the shape and volume of its container • compressible • lots of free space between particles • flows easily (particles can move past one another) • low density • SOLID • retains a fixed volume and shape • rigid - particles locked into place • not easily compressible • little free space between particles • does not flow easily • rigid - particles cannot move/slide past one another • high densitY • LIQUID • assumes the shape of the part of the container which it occupies • not easily compressible • little free space between particles • flows easily (particles can move/slide past one another) • high density

  7. *4D:  Classify matter as pure substances or mixtures through investigation of their properties.

  8. Pure Substance Pure Substance is: a substance with constant composition. Can be classified an either an element or as a compound. Element: a substance that cannot be separated into two or more substances by ordinary chemical (or physical) means. We use the term ordinary chemical means to exclude nuclear reactions. Elements are composed of only one kind of atom. Examples: Iron (Fe), copper (Cu), and oxygen (O2). Compound: a substance that contains two or more elements, in definite proportion by weight. The composition of a pure compound will be invariant, regardless of the method of preparation. Compounds are composed of more than one kind of atom. The term molecule is often used for the smallest unit of a compound that still retains all of the properties of the compound. Examples: Table salt (sodium chloride, NaCl), sugar (sucrose, C12H22O11), and water (H2O).

  9. 5A: Use of Element's Properties in Development of Periodic Table Mendeleev Dmitri I. Mendeleev -made cards of the elements and their properties - tried arranging cards to find a pattern -made a column of cards ranking highest to lowest mass -noted they had different properties started ranking cards according to properties also - left spaces when pattern didn't fit Law of Octaves John Newlands -arranged elements according to atomic weight - noticed that the pattern repeated every eighth element rejected because not all elements fit the pattern -model did not allow for discovery of new elements Triad Model Johan Dobereiner- elements fit in groups of three according to properties- atomic weight of the intermediate element was approximately the average of the other two- became outdated because new element did not fit in Modern Periodic Table Henry Moseley - took Mendeleev's table and arranged elements according to atomic number -bound elements fit the table more accurately

  10. *5B: Use the Periodic Table to Explain Properties of Families

  11. Alkali Metals Alkali Metals have one electron in the outermost orbital.Who's in the family? Starting at the top we find hydrogen (H). But wait. That element is NOT in the family. When we told you about families, we said that they were groups of elements that react in similar ways. Hydrogen is a very special element of the periodic table and doesn't belong to any family. While hydrogen sits in Group 1, it is NOT an alkali metal. Now that we've covered that exception, the members of the family include: lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) and francium (Fr). As with all families, these elements share traits. They are very reactive. Why? They all have one electron in their outer shell. That's one electron away from being stable. They bond with other elements by losing one electron and becoming an ion with a +1 charge. An increased tendency to bond means you are more reactive. In fact, when you put some of these pure elements in water (H2O), they can cause huge explosions.

  12. Alkaline Earth Metal So we just covered the alkali metals in Group I. You will find the alkaline earth metals right next door in Group 2. This is the second most reactive family of elements in the periodic table. Do you know why they are called alkaline? When these compounds are mixed in solutions, they are likely to form solutions with a pH greater than 7. Those higher pH levels means that they are defined as "basic" or "alkaline" solutions Who's in the family? The members of the alkaline earth metals include: beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra). As with all families, these elements share traits. While not as reactive as the alkali metals, this family make bonds very easily. Each of them has two electrons in their outer shell. They are ready lose those two electrons. Sometimes you will see them with two halogen atoms,as with beryllium fluoride (BeF2), and sometimes they might form a double bond, as with calcium oxide (CaO). It's all about giving up those electrons to form a +2 ion. As you get to the bottom of the list, you will find the radioactive radium. While radium is not found around your house anymore, it used to be an ingredient in glow-in-the-dark paints. It was originally mixed with zinc sulfide (ZnS). The other elements are found in many items, including fireworks, batteries, flashbulbs, and special alloys. The lighter alkaline earth metals, such as magnesium and calcium, are very iimportant in animal and plant physiology. You all know that calcium helps build your bones. Magnesium can be found iin chlorophyll molecules

  13. Halogens When you look at our descriptions of the elements fluorine and chlorine, you will see that they both have seven electrons in their outer shell. That seven-electron trait applies to all of the halogens. They are all just one electron shy of having full shells. Because they are highly reactive, they have the trait of combining with many different elements. They are very reactive. You will often findthem bonding with metals and elements from Group One of the periodic table. The elements in the column on the left each have one electron that they like to donate. We've just told you how reactive the halogens are. Not all halogens react with the same intensity or enthusiasm. Fluorine is the most reactive and combines with most elements from around the periodic table. Reactivity decreases as you move down the column. As the atomic number increases, the atoms get bigger. Their chemical properties change just a little bit when compared to the element right above them on the table.

  14. Noble Gas • Some scientists used to call them the inert gases.. The noble gases are another family of elements, and all of them are located in thefar right column of the periodic table. They are The Most Un-reactive (stable) Why? Using the Bohr description of electron shells, their atoms have full shells. All of the noble gases have full outer shells with eight electrons. Oh, wait! That's not totally correct. At the top of the noble gases is little helium (He), with a shell that is full with only two electrons. The fact that their outer shells are full means they are quite stable and don't need to react with other elements. In fact, they rarely combine with other elements. That non-reactivity is why they are called inert. The list includes helium, neon (Ne), argon (Ar), krypton (Kr), xenon (Xe), and radon (Rn). Don't think that, because these elements don't like to react, we don't use them. You will find noble gases all over our world. Neon is used in advertising signs. Argon is used in light bulbs. Helium is used in balloons and to cool things. Xenon is used in headlights for newcars. Because of their chemical properties, these gases are also used in the laboratory to help stabilize reactions that would usually proceed too quickly. Some do As of about 40 years ago, scientists have been able to make some compounds with noble gases. The thing to remember is that they were forced. When going about their natural lives, you will never (well, never say never, because there may be an exception) find the noble gases bonded to other elements.

  15. Transition Metals • It all has to do with their outer orbit using Bohr’s model. Transition metals are good examples of advanced shell and orbital ideas. They have a lot of electrons and distribute them in different ways. You will usually find that transition metals are shiny, too. Not all of them, but we are sure you've seen pictures of silver (Ag), gold (Au), and platinum (Pt). Transition metals are able to put more than eight electrons in the shell that is one in from the outermost shell. Think about argon (Ar). It has 18 electrons set up in a 2-8-8 order. Scandium (Sc) is only 3 spots away with 21 electrons, but it has a configuration of 2-8-9-2. You need to remember that those electrons are added to the second-to-last shells. The transition metals are able to put up to 32 electrons in their second-to-last shell. Something like gold (Au), with an atomic number of 79, has an organization of 2-8-18-32-18-1. Of course, there are still some rules.

  16. *5C: Periodic Trends Focus on the number of protons in the nucleus and the distance between the nucleus and outer energy level 1. Down a Group: The orbitals get further from the nucleus as you go down a group (outer orbital further from nucleus) causing the outer electrons to be less attracted by the nucleus down a group. 2. Down a Group the electrons in the inner energy levels repel the electrons in the outer energy level reducing the attraction the nucleus has on the outer energy level. This is called electron shielding. 3. Across a Period: The outer orbitals get are closer to the nucleus as you go left to right across a period because they have the same number of energy levels but the nucleus has a greater number of protons this increased attraction pulling the outer energy level closer to the nucleus.

  17. Atomic Radii • Group: Radius of atoms increase as you move from one atom to • the next down a group because each atom has an additional energy • level and electron shielding increases(the inside energy level • electrons repel the outer electrons reducing the ability of the nucleus to attract the outer energy level) making it which is further away Period: Radius decreases across a period because the atoms in a period have the same number of energy levels but the number of protons increase as you go from atom to atom across a period causing an increased attraction between the nucleus and the outer electrons resulting in the outer energy being pulled toward the nucleus making the radius smaller.

  18. Ionic Radii • Cations (positive charged ions, formed when metals lose • electrons) have smaller radii than their neutral atoms. • Cations are smaller because they lose the electron(s) in their outer energy level when forming ions. The nucleus has an increased ability to pull the energy levels even closer to the nucleus because there is a greater positive charge than negative charge Cations (positive charged ions, formed when metals lose electrons) have smaller radii than their neutral atoms. Cations are smaller because they lose the electron(s) in their outer energy level when forming ions. The nucleus has an increased ability to pull the energy levels even closer to the nucleus because there is a greater positive charge than negative charge

  19. Ionization Energy • GROUP: Moving down a group, 1st ionization energy decreases because the distance between the most loosely held electron and the nucleus increase from atom to atom as you go down a group resulting in a decrease attraction between the nucleus and outer electrons therefore less energy is required to remove the electron down a group Period: Moving across a period from left to right 1st ionization energy increases because the atoms in the same period have the same number of energy levels but the number of protons increase as you go from atom to atom across a period resulting in an increased attraction between the nucleus and the outer electrons therefore more energy is required to remove the outer most electron.

  20. Electronegativity • Electronegativity: is a measure of the ability of an atom to attract additional electron to it. • Group: Electronegativity decreases down a group because the outer energy level is further away from the nucleus which results in a weaker nuclear charge available to attract additional electrons or less ability for an atom to attract electrons to it. Period: Electronegativity increases moving across a period from left to right because the atoms in the same period have the same number of energy levels but the number of protons increase as you go from atom to atom across a period increasing the attraction between the nucleus and the outer energy level resulting in a greater ability for atoms to attract electrons to it.

  21. 4A Practice Questions 1.  Which of the following examples is evidence of a physical change?    a.  Ice cream melts in a bowl.    b.  A silver spoon tarnishes over time.    c.  An electric current splits water into hydrogen and oxygen.    d.  A person inhales oxygen and exhales carbon dioxide and water.2.  The table below shows the procedures for and results of two experiments using copper (II) chloride,CuCl2. Which of the following conclusions can be made based on the results of the experiments?    a.  Physical change occurred in both experiments.    b.  Chemical change occurred in both experiments.    c.  A chemical change occurred in experiment 1, and a physical change occurred in           experiment 2.    d.  A physical change occurred in experiment 2, and a chemical change occurred in          experiment 1.3.  Which of the following is a chemical property of iron?    a.  Density = 7.874 g/cm3    b.  Iron melts at 1808 K.    c.  Iron corrodes in moist air.    d.  Iron is soft when pure.

  22. 4A Practice Problems 1.  Which of the following examples is evidence of a physical change?a.  Ice cream melts in a bowl.b.  A silver spoon tarnishes over time.c.  An electric current splits water into hydrogen and oxygen.d.  A person inhales oxygen and exhales carbon dioxide and water. 3. Which of the following is a chemical property of iron? a. Density = 7.874 g/cm3 b. Iron melts at 1808 K. c. Iron corrodes in moist air. d. Iron is soft when pure. 4.  The following properties describe zinc.  List the chemical properties. I.  It is a bluish-white metal.II.  It corrodes upon prolong contact with moist air.III.  Its density is 7.14 g/cm3.IV.  It melts at 419 C.V.  It conducts electricity.    a.  I and II    b.  II only    c.  I, III, IV    d.  V only 2.  The table below shows the procedures for and results of two experiments using copper (II) chloride,CuCl2. Which of the following conclusions can be made based on the results of the experiments?a.  Physical change occurred in both experiments.b.  Chemical change occurred in both experiments.c.  A chemical change occurred in experiment 1, and a physical change occurred in   experiment 2.d.  A physical change occurred in experiment 2, and a chemical change occurred in experiment 1

  23. 4A Practice 5. If a certain mixture is homogeneous, you would properly conclude that the physical properties and the composition: a. are different from one part of the sample to another b. vary smoothly from top to bottom of the sample c. are the same in every small volume element from the sample d. none of these 6. Label each process as a physical or chemical change: a. Moth balls gradually vaporize in a closet b. hydrofluoric acid attacks glass (used to etch glassware) c. A chef making a sauce with brandy is able to burn off the alcohol from the brandy, leaving just the brandy flavoring d. Chlorine gas liquefies at -35 °C under normal pressure e. hydrogen burns in chlorine gas 7. Label each process as a physical or chemical change: a. fogging a mirror with your breath b. breaking a bone c. mending a broken bone d. burning paper e. slicing potatoes for fries f. mixing sugar with coffee g. frying chicken h. a nail rusting i. paper ripping j. wood burning k. mixing water and food coloring l. food molding (rotting) m. writing on paper n. dyeing fabric 1. Label each process as a physical or chemical change: a. perfume evaporating on your skin b. butter melting c. wood rotting d. charcoal heating a grill e. autumn leaves changing color f. a hot glass cracking when placed in cold water g. melting copper metal h. burning sugar i. mixing sugar in water j. digesting food 2. Which of the following would NOT be a physical change? a. freezing water to make ice cubes b. melting gold to make jewelry c. burning gasoline in a lawnmower d. boiling water for soup e. tearing a piece of aluminum foil 3. Which of the following is NOT a physical change? a. grating cheese b. melting cheese c. fermenting of cheese d. mixing two cheeses in a bowl 4. Which are physical and which are chemical changes? a. boil b. burn (combustion) c. condense d. corrode e. crumple f. ferment g. melt h. rust i. crush j. freeze k. oxidize l. tarnish m. explode n. grind o. rot p. vaporize q. photosynthesis r. sublimation

  24. 4A Practice Answers 5. If a certain mixture is homogeneous, you would properly conclude that the physical properties and the composition: c. are the same in every small volume element from the sample - the correct answer 6. Label each process as a physical or chemical change: a.Moth balls gradually vaporize in a closet - physicalb. hydrofluoric acid attacks glass (used to etch glassware) - chemicalc. A chef making a sauce with brandy is able to burn off the alcohol from the brandy, leaving just the brandy flavoring - chemical(evaporating physical)d. Chlorine gas liquefies at -35 °C under normal pressure - physicale. hydrogen burns in chlorine gas – chemical 7. Label each process as a physical or chemical change: a. fogging a mirror with your breath - physicalb. breaking a bone - physicalc. mending a broken bone - chemicald. burning paper - chemicale. slicing potatoes for fries - physicalf. mixing sugar with coffee - physicalg. frying chicken - chemicalh. a nail rusting - chemicali. paper ripping - physicalj. wood burning - chemicalk. mixing water and food coloring - physicall. food molding (rotting) - chemicalm. writing on paper - physicaln. dyeing fabric –depends on fabric/process 1. Label each process as a physical or chemical change: a.perfumeevaporating on your skin - physicalb. butter melting - physicalc. wood rotting - chemicald. charcoal heating a grill - see belowe. autumn leaves changing color - chemicalf. a hot glass cracking when placed in cold water - physicalg. melting copper metal - physicalh. burning sugar - chemicali. mixing sugar in water - physicalj. digesting food - chemical 2. Which of the following would NOT be a physical change? c. burning gasoline in a lawnmower - this one is NOT a physical change 3. Which of the following is NOT a physical change? grating cheese c. fermenting of cheese - this one is NOT a physical change 4. Which are physical and which are chemical changes? a.boil- physicalb. burn (combustion) - chemicalc. condense - physicald. corrode - chemicale. crumple - physicalf. ferment - chemicalg. melt - physicalh. rust - chemicali. crush - physicalj. freeze - physicalk. oxidize - chemicall. tarnish - chemicalm. explode - see comment belown. grind - physicalo. rot - chemicalp. vaporize - physicalq. photosynthesis - chemicalr. sublimation - physical

  25. 4B/4D Practice Label Each property as I-for intensive, or E-for extensive Melting/Freezing Point Boiling Point Density Volume Mass Weight Conductivity Hardness Color Odor Luster Malleability Length Underline each pure substance. Label everything underlined as E for element, or C for compound. Then, label everything not underlined as homogeneous (homo) or heterogeneous (het) Hydrogen wine Helium carbon monoxide Sand in water Carbon salty water Gold carbon dioxide Muddy water pure water table salt Blood0.5 M hydrochloric acid Given an unknown liquid, list three techniques could you use to tell if it were a mixture or pure substance. 1. 2. 3.

  26. 4B/4D Practice Ansswers Label Each property as I-for intensive, or E-for extensive Mass E Weight E Conductivity I Hardness I Melting/Freezing Point I Boiling Point I Density I Volume E Color I Odor I Luster I Malleability I Length E Hydrogen E wine HOM Helium E carbon monoxide C Sand in water HET Carbon E salty water HOM Gold Ecarbon dioxide C Muddy water HET pure water C table salt C Blood HOM0.5 M hydrochloric acid HOM Given an unknown liquid, list three techniques could you use to tell if it were a mixture or pure substance. 1.distillation 2.filtering 3.Magnetic (for metals)..or particle separation

  27. 5A Practice

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