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STAAR Reporting Category 1 Matter & Energy Atoms and Elements The Structure of an Atom electron (-) neutron (o) electron cloud ++ + + nucleus ++ Proton (+) Location and Mass of Atomic Particles Inside the Nucleus Protons with a POSITIVE charge AND Outside the Nucleus Electrons with a NEGATIVE charge VERY, VERY tiny and do not contribute to the mass of the Neutrons with a NEUTRAL atom charge (no charge) Both have about the same mass It takes 2000 electrons to equal the mass of one proton or neutron Elements are listed on the Periodic Table Atomic Number Number of PROTONS and determine which element the atom is Atomic Mass the number of PROTONS + NEUTRONS How do I calculate # of NEUTRONS??? First, round the atomic mass to the nearest whole number Round to 28 Then, subtract the Atomic number (# protons) from the Atomic mass (total # protons and neutrons 28 (Atomic mass) -14 (Atomic number) 14 NEUTRONS Is there an EASIER way to remember all of this? All you have to do is remember: A=P=E M-A=N A=P=E Atomic Number = If I know ONE, I know them Protons ALL!! = Electrons M-A=N Mass Atomic Number = Neutrons PRACTICE TIME Use your Periodic Table!! Symbol Atomic # Mass # # Protons # Neutrons # Electrons He 2 4 2 2 2 Li 3 7 3 4 3 N 7 14 7 7 7 Electrons and Bohr Diagrams 1) Find your element on the periodic table. 2) Determine the number of electrons – remember, it is the same as the atomic number. 3) This is how many electrons you will draw. Bohr Diagrams 6P 6N Draw a nucleus with the number of protons and neutrons inside. Bohr Diagrams 6P 6N 1) Add the electrons. 2) Carbon has 6 electrons. 3) The first shell can only hold 2 electrons. Always start in the first shell Bohr Diagrams 6P 6N 1) Since you have 2 electrons already drawn, you need to add 4 more. 2) These go in the 2nd shell. Bohr Diagrams 6P 6N 1) Check your work. 2) You should have 6 total electrons for Carbon. 3) Only two electrons can fit in the 1st shell. 4) The 2nd and 3rd shells can hold up to 8 electrons. Bohr Diagrams Try the following elements on your own: a) b) c) d) e) f) H He O Al Ne K Bohr Diagrams Try the following elements on your own: 1P a) b) c) d) e) f) H – 1 electron He O Al Ne Na Bohr Diagrams Try the following elements on your own: 2P 2N a) b) c) d) e) f) H He - 2 electrons O Al Ne Na Bohr Diagrams Try the following elements on your own: 8P 8N a) b) c) d) e) f) H He O - 8 electrons Al Ne Na Bohr Diagrams Try the following elements on your own: 13 P 14 N a) b) c) d) e) f) H He O Al - 13 electrons Ne Na Bohr Diagrams Try the following elements on your own: 10 P 10 N a) b) c) d) e) f) H He O Al Ne - 10 electrons Na Bohr Diagrams Try the following elements on your own: 11 P 12 N a) b) c) d) e) f) H He O Al Ne Na - 11 electrons Valence Electrons • Found on the outermost energy level –Determine how an element will react chemically Lewis Structures How many valence electrons does nitrogen have? 5 Learning Check How many valence electrons in each atom? Heliu m Oxygen Sodium 2 6 1 Charges of Atoms Most atoms have a NEUTRAL CHARGE since they have equal numbers of protons (+) and electrons (-). Some atoms gain or lose electrons to become IONS. IONS are not neutral and the atom becomes positively or negatively charged. Let’s see how this works... in an atom, protons ( + ) are in the center and electrons ( ) are on the outside + ++ + + only electrons ( ) can be added or taken away + ++ + + this is an atom with 5 electrons and 5 protons + ++ + + the atom is neutral net charge = zero + ++ + + 5 (-) and 5 (+) = zero charge (neutral) charge = ? 6 (-) and 5 (+) = -1 + ++ + + charge = ? 3 (-) and 5 (+) = +2 + ++ + + WHEN REMOVING ELECTRONS THE RESULTING CHARGE IS POSITIVE neutral +1 WHEN ADDING ELECTRONS THE RESULTING CHARGE IS NEGATIVE neutral -2 Elements are substances: • that cannot be broken down into other substances • that are made of atoms with the same number of protons in the nucleus Elements are ORGANIZED on the Periodic Table Elements with similar properties are placed in the same group in the periodic table. The stair-step line separates the elements into metals and nonmetals. Groups of Elements Alkali Metals • Group 1, highly reactive, 1 valence electron • Soft metals with low melting points The Periodic Table of Elements 1 1 2 3 4 5 6 7 H 2 Li Be Na Mg K Ca Rb Sr Cs Ba Fr Ra 18 13 3 4 Sc Y Lu Lr Ti Zr Hf Rf 5 6 7 8 V Cr Mn Fe Nb Mo Tc Ru Ta W Re Os Db Sg Bh Hs 9 Co Rh Ir Mt B 10 11 12 Al Ni Cu Zn Ga Pd Ag Cd In Pt Au Hg Tl Ds Rg 14 15 16 17 C Si Ge Sn Pb N P As Sb Bi O S Se Te Po F Cl Br I At La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No He Ne Ar Kr Xe Rn Alkaline Earth Metals • Group 2, reactive, 2 valence electrons • Hard metals with high melting points The Periodic Table of Elements 1 1 2 3 4 5 6 7 H 2 Li Be Na Mg K Ca Rb Sr Cs Ba Fr Ra 18 13 3 4 Sc Y Lu Lr Ti Zr Hf Rf 5 6 7 8 V Cr Mn Fe Nb Mo Tc Ru Ta W Re Os Db Sg Bh Hs 9 Co Rh Ir Mt B 10 11 12 Al Ni Cu Zn Ga Pd Ag Cd In Pt Au Hg Tl Ds Rg 14 15 16 17 C Si Ge Sn Pb N P As Sb Bi O S Se Te Po F Cl Br I At La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No He Ne Ar Kr Xe Rn Transition Metals • Group 3-12, variable # of valence electrons • Unpredictable, don’t follow “reactivity” rules The Periodic Table of Elements 1 1 2 3 4 5 6 7 H 2 Li Be Na Mg K Ca Rb Sr Cs Ba Fr Ra 18 13 3 4 Sc Y Lu Lr Ti Zr Hf Rf 5 6 7 8 V Cr Mn Fe Nb Mo Tc Ru Ta W Re Os Db Sg Bh Hs 9 Co Rh Ir Mt B 10 11 12 Al Ni Cu Zn Ga Pd Ag Cd In Pt Au Hg Tl Ds Rg 14 15 16 17 C Si Ge Sn Pb N P As Sb Bi O S Se Te Po F Cl Br I At La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No He Ne Ar Kr Xe Rn Halogens • Group 17, highly reactive, 7 valence electrons • Form “salts” The Periodic Table of Elements 1 1 2 3 4 5 6 7 H 2 Li Be Na Mg K Ca Rb Sr Cs Ba Fr Ra 18 13 3 4 Sc Y Lu Lr Ti Zr Hf Rf 5 6 7 8 V Cr Mn Fe Nb Mo Tc Ru Ta W Re Os Db Sg Bh Hs 9 Co Rh Ir Mt B 10 11 12 Al Ni Cu Zn Ga Pd Ag Cd In Pt Au Hg Tl Ds Rg 14 15 16 17 C Si Ge Sn Pb N P As Sb Bi O S Se Te Po F Cl Br I At La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No He Ne Ar Kr Xe Rn Noble Gases • Group 18, full outer shells (2 in He and 8 in others) • NON-REACTIVE The Periodic Table of Elements 1 1 2 3 4 5 6 7 H 2 Li Be Na Mg K Ca Rb Sr Cs Ba Fr Ra 18 13 3 4 Sc Y Lu Lr Ti Zr Hf Rf 5 6 7 8 V Cr Mn Fe Nb Mo Tc Ru Ta W Re Os Db Sg Bh Hs 9 Co Rh Ir Mt B 10 11 12 Al Ni Cu Zn Ga Pd Ag Cd In Pt Au Hg Tl Ds Rg 14 15 16 17 C Si Ge Sn Pb N P As Sb Bi O S Se Te Po F Cl Br I At La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No He Ne Ar Kr Xe Rn Rare Earth Elements • Group 3, Period 6 and 7 • Special group of transition metals • Many are synthetic and/or radioactive The Periodic Table of Elements 1 1 2 3 4 5 6 7 H 2 Li Be Na Mg K Ca Rb Sr Cs Ba Fr Ra 18 13 3 4 Sc Y Lu Lr Ti Zr Hf Rf 5 6 7 8 V Cr Mn Fe Nb Mo Tc Ru Ta W Re Os Db Sg Bh Hs 9 Co Rh Ir Mt B 10 11 12 Al Ni Cu Zn Ga Pd Ag Cd In Pt Au Hg Tl Ds Rg 14 15 16 17 C Si Ge Sn Pb N P As Sb Bi O S Se Te Po F Cl Br I At La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No He Ne Ar Kr Xe Rn Metalloids • Non-metal elements that are conductors of heat and electricity The Periodic Table of Elements 1 1 2 3 4 5 6 7 H 2 Li Be Na Mg K Ca Rb Sr Cs Ba Fr Ra 18 13 3 4 Sc Y Lu Lr Ti Zr Hf Rf 5 6 7 8 V Cr Mn Fe Nb Mo Tc Ru Ta W Re Os Db Sg Bh Hs 9 Co Rh Ir Mt B 10 11 12 Al Ni Cu Zn Ga Pd Ag Cd In Pt Au Hg Tl Ds Rg 14 15 16 17 C Si Ge Sn Pb N P As Sb Bi O S Se Te Po F Cl Br I At La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No He Ne Ar Kr Xe Rn Periodic Trends • Elements are arranged into horizontal rows called PERIODS • Elements within a period have the same number of ENERGY LEVELS The Periodic Table of Elements 1 1 energy level 1 2 energy levels 2 3 energy levels 3 4 energy levels 5 energy levels 4 6 energy levels 6 7 energy levels 7 5 18 H 2 Li Be Na Mg 3 K Ca Sc Rb Sr Y Cs Ba Lu Fr Ra Lr 13 4 Ti Zr Hf Rf 5 6 7 8 V Cr Mn Fe Nb Mo Tc Ru Ta W Re Os Db Sg Bh Hs 9 Co Rh Ir Mt B 10 11 12 Al Ni Cu Zn Ga Pd Ag Cd In Pt Au Hg Tl Ds Rg 14 15 16 17 C Si Ge Sn Pb N P As Sb Bi O S Se Te Po F Cl Br I At La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Ac Th Pa U Np Pu AmCm Bk Cf Es Fm Md No He Ne Ar Kr Xe Rn • Elements are arranged in vertical columns called GROUPS 5 6 7 4 Sc Y Lu Lr Ti Zr Hf Rf 5 6 7 8 V Cr Mn Fe Nb Mo Tc Ru Ta W Re Os Db Sg Bh Hs 9 Co Rh Ir Mt 13 14 15 16 17 C Si Ge Sn Pb N P As Sb Bi O S Se Te Po F Cl Br I At B 10 11 12 Al Ni Cu Zn Ga Pd Ag Cd In Pt Au Hg Tl Ds Rg La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No 8 valence electrons 7 valence electrons 4 3 6 valence electrons 3 5 valence electrons 2 H 2 Li Be Na Mg K Ca Rb Sr Cs Ba Fr Ra 4 valence electrons 1 The Periodic Table of Elements 3 valence electrons 1 2 valence electrons 1 valence electron – have same number of VALENCE ELECTRONS – share similar CHEMICAL properties 18 He Ne Ar Kr Xe Rn Metal Properties • • • • • Shiny solids Ductile (able to be stretched) Malleable (able to be shaped) Good conductors of heat and electricity Magnetic Nonmetal Properties • • • • May be solids, liquids or gases Dull, brittle solids Poor conductors of heat and electricity Non-magnetic Metalloid Properties • Nonmetals with properties of both metals and non-metals • Weak conductors of heat and electricity Atomic Theory Atoms are building blocks of elements Atoms in each unique element are the same. (Ex: Every oxygen element has the same # of protons) Atoms are different from atoms of other elements (Ex: Hydrogen has a different # of protons than oxygen) Two or more different atoms bond in simple ratios to form compounds (Ex: Hydrogen & oxygen can chemically combine to form water- H2O ) Writing Chemical Symbols 1. First letter is capitalized 2. Second letter is lower case 3. NO period at the end H Cl O Hg Fe Sn C He Does it really matter? Co or CO Co = cobalt Alloys for metals used in jet turbines CO carbon oxygen carbon monoxide Colorless Odorless Poisonous gas Compounds 2 or More Elements Chemically Combined Hydrogen 2-H: 1-O Hydrogen Oxygen Ratio 2:1 H H O H2O 1 is not shown Formulas use element symbols with subscript numbers Water Change the ratio Change the substance Hydrogen 2:2 Peroxide H2O2 Subscript numbers http://www.wonderquest.com/images/2003-08-08-peroxide.jpg No subscripts?? 1Na NaCl Salt 1Cl How many elements? 2 Chemical Changes A chemical change is a change in which both the physical and chemical properties of the original substance are changed. The new substance has new physical and chemical properties. Burning is a chemical change. A chemical change is the result of a Chemical Reaction. A chemical reaction occurs when atoms separate, come together, or rearrange to form new substances with new properties. Example of a Chemical Reaction Reactant + Reactant Product (goes to) carbon + oxygen carbon dioxide (has different properties) C + O2 CO2 Is the product the same as the reactants? No, the atoms have been rearranged. For Example… A chemical reaction takes place during photosynthesis. 6CO2 + 6H2O C6H12O6 + 6O2 Carbon dioxide reacts with water to form glucose (a sugar) and oxygen. copper + oxygen copper oxide 2 Cu O2 Cu O Cu O 2 CuO CuO CuO balanced 2 copper atoms 2 oxygen atoms in a molecule (O2) 2 copper atoms 2 oxygen atoms 2 copper atoms 2 copper atoms =balanced= 2 oxygen atoms 2 oxygen atoms Since nothing is lost or gained, there is no loss or gain in mass (atoms). You can say the equation is balanced. The Law of conservation of mass states that matter cannot be created or destroyed in any chemical reaction The atoms in the reactants are rearranged to form new compounds, but none of the atoms disappear, and no new atoms are formed. H H H H Reactants O O Products Remember that atoms don’t change in a chemical reaction. • The number and kinds of atoms present in the reactants of a chemical reaction are the same as those present in the products. When stated this way, it becomes the law of conservation of atoms. So: Chemical equations are balanced, when the numbers and kinds of atoms on each side of the reaction arrow are equal. H H H H O H O O H H Reactants Products 4 Hydrogen 4 Hydrogen 2 Oxygen 2 Oxygen H O Coefficients, the numbers placed in front of formulas to balance equations, indicate the number of particles present in the reaction. If a number is not present it is understand that 1 is the coefficient. 2 H2 + O2 2 H2O 2 2 The number of oxygen atoms are not the same so the equation is balanced with coefficients. Notice that the number of hydrogen and oxygen atoms are equal The same number of each kind of atom must be on the left side of the arrow as are on the right side when an equation is balanced. Al Al Al Al O O O O O O When an equation is balanced the number of reactant atoms will always equal the number of product atoms and atoms are conserved O Al O Al O O Al O Al O O O Al Al O O AlAl O O Chemical Equations • Many times it may seem that things we use disappear over time. For example, gasoline in the car. • Elements of gasoline are merely re-arranged through a chemical reaction. Gasoline CO2 and H2O • The number of each type of element and their masses remain unchanged (balanced) in a chemical reaction. (Law of Conservation of Mass) • A chemical equation is a way to describe or represent what goes on in a chemical reaction and follows the Law of Conservation of Mass. • Matter cannot be created or destroyed – ONY rearranged into different substances. Chemical and Physical Change Organic Compounds • Compounds that includes CARBON along with other element(s) hydrogen, nitrogen, phosphorous, and or sulfur. • Nucleic Acid (DNA), Carbohydrates, Proteins, & Starch. Is it Organic? C6H12O6 YES Ca3Si2O7 no NaCl no C3H8 YES Fe2O3 no C5H11NO2S CuSO4 CH3COOH Ca5(PO4)3OH C27H46O YES no YES no YES The transfer of energy from the sun to producer to primary consumer to secondary consumer to tertiary consumer can be shown in a FOOD CHAIN. The arrow shows the flow of energy, first from the sun to the producers and then to each organism in the food chain. Food Webs: • Are interconnected food chains • They show the feeding relationships in an ecosystem • Arrows point in direction of energy flow Another way of showing the transfer of energy in an ecosystem is the ENERGY PYRAMID. Energy pyramids show .1% 1% 10% 100% • That the amount of available energy decreases down the food chain • Only 10 % of the energy is passed to the next level • It takes a large number of producers to support a small number of primary consumers • It takes a large number of primary consumers to support a small number of secondary consumers What is density? • Density is a comparison of how much matter there is in a certain amount of space. What is density? • Density = mass OR volume • Units for density: g OR g mL mass ÷ volume. ALWAYS REMEMBER cm3 UNITS! Density Problems • Frank has a paper clip. It has a mass of 9 g and a volume of 3 cm3. What is its density? D=m v D=9g 3 cm3 D = 3 g/cm3 • Frank also has an eraser. It has a mass of 3 g, and a volume of 1cm3. What is its density? D=m v D=3g 1 cm3 D = 3 g/cm3 • Jack has a rock. The rock has a mass of 6 g and a volume of 3 cm3. What is the density of the rock? D=m v D=6g 3 cm3 D = 2 g/cm3 • Jill has a gel pen. The gel pen has a mass of 8 g and a volume of 2 cm3. What is the density of the pen? D=m v D=8g 2 cm3 D = 4 g/cm3 • Al’Licia has a watch. It has a mass of 4 g and a volume of 2 cm3. What is the density of the watch? D=m v D=4g 2 cm3 D = 2 g/cm3 • Mia has a wallet. It has a mass of 15 g and a volume of 5 cm3. What is the density of the wallet? D=m v D = 15 g 5 cm3 D = 3 g/cm3 √ Check your understanding 1. The symbol for carbon is – A Ca B c C CA D C 2. How many protons are in an atom of sodium? A 11 B 12 C 23 D 34 3.How many neutrons are there, if the mass number is 1 and the atomic number is 1? A 3 B 2 C 1 D 0 4.How many electrons are in an atom of Cl? A 17 B 18 C 35 D 0 5.Which of the following is a chemical formula? A H B O C H2O D h2o 6.How many different elements are in baking soda, NaHCO3 ? A 6 B 5 C 4 D 3 7. Which of the following situations contains an example of a chemical reaction? A B C D Ice forming after water is placed in a freezer Watercolor paint drying on paper A sugar cube dissolving in a glass of water A bicycle rusting after it is left in the rain C6H12O6 + 6 O2 6 H2O + 6 CO2 HCl + NaOH H2O + NaCl 8. Based on the data above, which statement is not true about chemical equations? A. Products are the rearrangement of atoms from the reactants. B. There are always more atoms on the reactant side of the equation than the product side. C. The types of atoms in the products will be the same as the types of atoms in the reactants. D. The mass and number of reactant atoms always equals the mass and number of product atoms. 9. Which chemical reaction is balanced? A. C + O2 2 CO2 B. 2 C + O2 2 CO2 C. 2 C + 2 O2 2 CO2 10. Which chemical reaction is balanced? A. HBr + Mg H2 + MgBr2 B. 2 HBr + Mg H2 + MgBr2 C. 2 HBr + 2 Mg H2 + 2 MgBr2