BASIS AHWATUKEE Chemistry 7 2024-2025 Pre-Comp Study Guide PDF

PRE-COMPREHENSIVE **STUDY GUIDE** 2024-2025 BASIS AHWATUKEE Chemistry 7 Ang **Name (Print):** \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ **Group:** \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ **STUDY GUIDE DIRECTIONS:** 1. **[Print]** your name and element on this p...

PRE-COMPREHENSIVE **STUDY GUIDE** 2024-2025 BASIS AHWATUKEE Chemistry 7 Ang **Name (Print):** \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ **Group:** \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ **STUDY GUIDE DIRECTIONS:** 1. **[Print]** your name and element on this page. 2. The Pre-Comp Periodic Table is included in the packet. 3. You will be allowed a scientific calculator and a periodic table during the exam so make sure you know how to use it correctly! 4. This packet is divided into **[two sections]** a. Key Topics to Review (Pages 3-10) i. b. Practice Problems (Pages 11-25) ii. **[Helpful Reminders]** **[Study Tips]** c. Read through the entire study guide before starting your work d. Prioritize studying your weakest topics iii. iv. e. **[Annotate this guide]** (highlight important concepts, star things that you need to heavily review, make notes to yourself) f. Look at old worksheets, tests/quizzes, Do Nows! **[What to Expect on Test Day]** g. There will be **[2 exams]**: v. 1. 25 multiple choice questions vi. 2. 32 questions which may be multiple choice or free-response h. You will have 30 minutes to complete [each] exam **[Additionally, The Periodic Table that is in this review packet is the exact format of the Periodic Table that BASIS will give you]** to complete your pre-comp make sure you know where to locate information that may be helpful to you answering questions asked of you to complete. **[Key Topics to Review]** ***Lab Safety Rules*** 1. Always read the lab and complete any pre-lab assignments before starting an experiment 2. Be aware of potential risks (e.g. flammability, toxicity) you may encounter 3. Keep work area clean and clear 4. Handle glassware with care and heating sources with caution 5. No horseplay to avoid accidents 6. Never eat or drink in lab 7. Inform teacher of spills or breakages immediately 8. Never pour chemicals down a sink unless instructed by the teacher ***PPE & Chemical Exposure Prevention*** - There are three pathways a chemical can enter your body: - **[Absorption]** - **[Ingestion]** - **[Inhalation]** - We can prevent chemicals from entering these pathways through: - Wearing **[goggles]** to prevent chemicals from getting into eyes - Not wearing contact lenses in lab - Wearing **[closed toe shoes]** to protect feet from spills or broken glass - Keeping **[hair tied back]** - Wearing **[gloves]** when working - Wear **[long sleeves/pants]** to avoid exposing skin to chemicals ***Safety Symbols*** - Be able to identify Globally Harmonized Safety (GHS) Symbols shown below - Be able to read and identify **National Fire Protection Agency (NFPA) Labels** - What each of the colors means: - **[Blue]** (left-most box)- indicates **health hazard** - **[Yellow]** (right-most box)- indicates **reactivity** - **[Red]** (top-most box)- indicates **flammability** - **[White]** (bottom-most box)- indicates **special warnings** - [Examples:] - COR= corrosive - ~~W~~= no water - What each number means: - 0- Not Hazardous - 1- Slightly Hazardous - 2- Moderately Hazardous - 3- Hazardous - 4- Extremely Hazardous ***Emergency Equipment*** - Be able to know the circumstances and functions of each of the following pieces of emergency equipment: **[fire extinguisher]**, **[fire blanket]**, **[fire alarm]**, **[gas shutoff]**, **[safety shower],** **[fume hood]**, and **[eye wash]** ***Lab Tools*** - Be able to identify pictures of the following lab tools and the purpose of those lab tools: **[mass balance]**, **[graduated cylinder]**, **[Erlenmeyer flask]**, **[beaker]**, **[test tube]**, **[volumetric flask]**, **[Bunsen burner]**, **[hot plate]**, **[watch glass]**, **[pipette]**, **[funnel]**, and **[thermometer]** ***Unit Conversions*** - Be able to convert from unit with prefix (i.e. kilo-, deca-, milli-, etc.) to base units - Be able to convert from base units to unit with prefix (i.e. kilo-, deca-, milli-, etc.) - Be able to convert from one prefixed unit to a different prefixed unit ***SI Units and Chemistry Units*** - Know SI units used for general science - SI units are **[kilogram]**, **[meters]**, **[meters cubed]**, **[seconds]**, and **[Kelvin]** - Know what units we use in Chemistry - Typically we use **[grams]**, **[milliliters]**, **[centimeters cubed]**, **[Kelvin]**, or **[Celsius]** ***Accuracy vs. Precision*** - Know that something with **[accuracy]** hits our mark even if not consistent - Know that something with **[precision]** shows consistency but isn't correct ***Measuring Volume Precisely*** - Understand that to measure volumes, you must look to the bottom of the **[meniscus]** - Know what lab tools allow you to look at volume more precisely than others ***Density*** - Understand the relationship between the variables of **[mass]**, **[volume]**, and **[density]** and how to calculate each based on only two of those given variables - Be able to identify that the substance with the **[greater density]** will **[sink]** - Be able to identify that the substance with the **[smaller density]** will **[float]** ***Archimedes Principle & Displacement*** - Be able to calculate the volume, density, or mass of an object using **[Archimedes Principle]** which is represented by the following equation: ***V~object~= V~final~ -- V~initial~*** ***Classifying Matter*** - Be able to classify substances as either an **[element]**, a **[compound]**, a **[heterogenous mixture]**, or a **[homogeneous mixture]** based on a diagram, a chemical formula, or a description of the substance - Be able to identify the 7 **[diatomic molecules]**: **H~2~**, **N~2~**, **O~2~**, **F~2~**, **Br~2~**, **Cl~2~**, **I~2~** - Identify the different parts of mixtures: - Homogenous Mixtures - Composed of **[solute]** which is the part that is **dissolved** and **changes state** - Also composed of **[solvent]** which **does the dissolving**, **does not change state,** and is typically present in a **larger amount** - Heterogenous Mixtures - Composed of **[solution]** which is **homogenous** - May be composed of a suspension and/or a precipitate - A **[suspension]** is **spread throughout** the solution - A **[precipitate]** **clumps** together to float or sink in a solution ***Separation Techniques*** - **[Filtration]**- separating substances based on **particle size** - **[Evaporation]**- separating substances based on **boiling point** - **[Chromatography]**- separating substances based on **solubility** - **[Decantation]**- separating substances based on **density** ***States of Matter*** - Be able to compare and contrast the different states of matter: solids, liquids, and gases like shown in the diagram below. **Trait** **Solid** **Liquid** **Gas** ------------------------------------ ---------------------------------------------------------- --------------------------------------------- ----------------------------------------------- Amount of Energy Little energy Some energy Lots of energy Movement Some vibrational movement but mostly stuck in same place Particles may slide past one another Particles move fast and bounce off each other Shape and Volume Definite shape and volume Definite volume but no definite shape No definite shape or volume Particles Distance From Each Other Particles packed closely together Particles stick close together but can move Particles spread out ***Phase Changes*** - Be able to identify the names associated with phase changes and energy and/or particles change - Solid Liquid (**[Melting]**) - Liquid Gas (**[Vaporization/Evaporation]**) - Gas Liquid (**[Condensation]**) - Liquid Solid (**[Freezing]**) - Solid Gas (**[Sublimation]**) - Gas Solid (**[Deposition]**) ***Physical vs. Chemical Changes*** - Be able to identify a **[physical change]** has occurred because there is a **change to the extensive properties** (cut, broken, sliced, spilled, etc.), a **phase change occurs**, or **two substances are mixed/combined** - Be able to identify a **[chemical change]** has occurred because there is a **change to the intensive properties** (color, texture, odor, luster, reactivity, flammability), a **new product is formed** that is not the same as the reactants, or there is evidence of **energy released or absorbed** in the form of sound or heat ***Atomic Structure*** - Understand that **[protons]** are the **positively charged** particles in atoms that are found in the **nucleus** and are **used to identify the element** because it's value never changes - Understand that **[neutrons]** are the **neutrally charged** particles in atoms that are found in the **nucleus** and are **used to count the mass of an atom** because it's value may change - **[Isotopes]** are elements with **different masses** because they have different numbers of neutrons - Understand that **[electrons]** are the **negatively charged** particles in atoms that are found in **electron clouds** and **sometimes used to identify the element** because our atom may be (un)charged - **[Ions]** are elements with **different charges** because they have different numbers of electrons - Two Types: - **[Cations]** (positively charged atom, **more protons than electrons**) - **[Anions]** (positively charged atom, **more electrons than protons**) ***Reading the Periodic Table*** - Classify elements from Periodic Table into **[metals]** (left of the metalloids), **[metalloids]**, and **[nonmetals]** - Understand that we use the word **[period]** to describe the **rows** of the Periodic Table which also defines the **energy level of the valence electrons** - Understand that we use the word **[group]** to describe the **columns** of the Periodic Table which also defines the **number of valence electrons** - Be able to represent elements, ions, and isotopes using: - **[Nuclear Symbol Notation]** - **[Hyphen Notation]** \[element name\]- \[mass \#\] [For example:] Carbon-14 ***Families of the Periodic Table*** - Be able to identify that: - Elements in **Group 1** belong to the **[Alkali Metals]** family - Elements in **Group 2** belong to the **[Alkaline Earth Metals]** family - Elements in **Groups 3-12** belong to the **[Transition Metals]** family - Elements in **Group 17 or 7a** belong to the **[Halogens]** family - Elements in **Group 18 or 8a** belong to the **[Noble Gases]** family - The elements, **B, Si, Ge, As, Sb, Te, and sometimes Po and At** belong to the **[Metalloids]** family ***Periodic Trends*** - Be able to predict which element(s) have a larger or smaller **[atomic radii]** - Remember that **[atomic radius]** is the **radius from the nucleus to the outermost shell of an atom** so this trend **increases from top to bottom** and **decreases left to right** - Be able to predict which element(s) have a larger or smaller **[ionization energy]** - Remember that **[ionization energy]** is the **energy required to remove an electron from an atom** so this trend **increases from left to right** and **decreases top to bottom** - Be able to predict which element(s) have a larger or smaller **[electronegativity]** - Remember that **[electronegativity]** is an **atom's attraction to the electrons of another atom** so this trend **increases from left to right** and **decreases top to bottom** ***Electrons & Oxidation Numbers*** - Identify the number of **[valence electrons]** in an element which are the **electrons in the outermost shell** that **participate in reactions** - To calculate **count "boxes" in period to get to element** - Identify the number of **[core electrons]** in an element which are **all the electrons underneath the outermost shell** that **stabilize the atom** - To calculate **subtract valence electrons from mass number** - Be able to identify an element's ionic charge or oxidation number based on it's family - **[Group 1]**: form **+1 charge** - **[Group 2]**: form **+2 charge** - **[Group 15]**: form **-3 charge** - **[Group 16]**: form **-2 charge** - **[Group 17]**: form **-1 charge** - **[Group 18]**: **do not form a charge** because they have a full valence shell ***Orbitals*** - Understand that different orbitals form different shapes as they pass by each other because of electron repulsion and attraction - Identify the 4 Types of Orbitals: - **[S Orbital]** - **Spherical shape** - **Can hold 2 electrons** per orbital - Valence electrons found in **Groups 1-2** - **[P Orbital]** - **Dumbbell shaped** - **Can hold 6 electrons** per orbital - Valence electrons found in **Groups 13-18** - **[D Orbital]** - **Clover shaped** - **Can hold 10 electrons** per orbital - Valence electrons found in **Groups 3-12** - **[F Orbital]** - **Flower shaped** - **Can hold 14 electrons** per orbital - Valence electrons found in **Lanthanides** and **Actinides** ***Ionic Bonding*** - Be able to name and write the chemical formulas of ionic compounds - **[Naming Type I Binary Compounds Steps:]** 1. Write element name of metal 2. Change suffix of nonmetal to -ide - **[Naming Type II Binary Compounds Steps:]** 1. Write element name of metal (which will be a transition metal) 2. Use a Roman Numeral to indicate charge of transition metal 3. Change suffix of nonmetal to -ide - **[Naming PAI Compounds (where PAI is acting as nonmetal) Steps:]** 1. Name metal 2. Name polyatomic ion - **[Naming PAI Compounds (where PAI is acting as metal) Steps:]** 1. Name PAI 2. Change suffix of nonmetal to -ide ***Covalent Bonding*** - Be able to name and write the chemical formulas of covalent compounds - **[Steps to Covalent Nomenclature:]** 1. Write first element (less electronegative element) followed by second element (more electronegative element) \*unless you are working with oxygen/oxide which [ALWAYS] is listed last 2. Determine how many atoms of each element are in compound 3. Give both elements a prefix based on \# of atoms 4. Add -ide suffix to second element listed (unless it's a PAI, then you would not change the name of the PAI) 5. DO NOT use mono- prefix for first element ***Lewis Structures*** - Be able to draw Lewis Dot Structures for individual elements and/or compounds by determining the \# of valence electrons the substance has - Each "**[dot]**" represents **1 valence electron** - Each "**[line]**" in a covalent compound represents ***2 valence electrons*** bring shared **[Unit 1: Laboratory Safety, Measurement, and Significant Figures]** 1. Name each hazard.  2. Name each piece of lab equipment and indicate (circle or highlight) which item(s) measure with precision.  3. List the four rules for counting significant figures. 4. Determine the number of significant figures in each of the following values. a. 0.0150 cm \_\_\_\_\_\_\_\_****\_\_\_\_\_\_\_ d. 0.0400 mol/L \_\_\_\_\_\_\_\_****\_\_\_\_\_\_\_ b. 2500 mL \_\_\_\_\_\_\_\_****\_\_\_\_\_\_\_ e. 100. \_\_\_\_\_\_\_\_****\_\_\_\_\_\_\_ c. 3.010 x 10^5^ s \_\_\_\_\_\_\_\_****\_\_\_\_\_\_\_ f. 50 beans \_\_\_\_**[infinite]**\_\_\_\_\_ 5. Use the tools below to measure the following objects **[to the correct precision]**. d.  e. 6. Calculate the following values to the correct number of sig figs. f. 4.35 + 7.1= \_\_\_\_\_**[11.5]**\_\_\_\_\_\_\_\_ d. 49.005 + 3 = \_\_\_\_\_****\_\_\_\_\_\_\_ g. 32.587 -- 9.1= \_\_\_\_\_**[23.5]**\_\_\_\_\_\_\_\_ e. 9.7 -- 3.516= \_\_\_\_\_**[6.2]**\_\_\_\_\_\_\_\_ h. 10.3 + 8.157=\_\_\_\_\_**[18.5]**\_\_\_\_\_\_\_\_ f. 8.4 -- 3.741=\_\_\_\_\_**[4.7]**\_\_\_\_\_\_\_\_ **[Unit 2 &3: Types, Properties, and States of Matter]** 7. Classify each of the following as either of a property of a solid, liquid, or gas. i. Indefinite shape, definite volume **(Liquid)** j. Lowest energy state of matter **(Solid)** k. Particles close together **(Solid)** l. Highest energy state of matter **(Gas)** 8. Fill in the following categorizing matter chart and then define those terms on the next page.  - **[Pure Substances:]** substances that are chemically bonded and cannot be physically separated - **[Mixtures:]** substances that are not chemically bonded and can be physically separated - **[Elements:]** a substance that cannot be broken down by chemical means - **[Compounds:]** a substance with two or more elements that are chemically combined - **[Homogenous Mixtures:]** mixtures made up of two or more substances that are uniform in composition but may have variable proportions - **[Heterogenous Mixtures:]** mixtures made up of two or more substances that has a variable composition and different proportions of molecules throughout them - - **[Solution:]** the homogenous liquid mixture of a heterogenous liquid - **[Suspension:]** solid substances in heterogenous mixtures that are spread throughout the mixture's solution - **[Precipitate:]** solid substances in heterogenous mixtures that clump together and float or sink to the bottom of a mixture's solution - **[Solute:]** dissolved part of a homogenous mixture which may change state and is present in a smaller amount - **[Solvent:]** part that does the dissolving of a solute in a homogeneous mixture, which typically keeps its state of matter and is present in a larger amount 9. Classify each of the following properties of matter as physical (P) or chemical(C). m. Density **(P)** n. Reacts with water**(C)** o. Sour taste **(C)** p. Malleable **(P)** q. Boils at 200^o^C **(P)** 10. Classify each of the following changes as physical (P) or chemical (C). r. Dissolving salt in water **(P)** s. Stretching copper into wire **(P)** t. Burning gasoline **(C)** u. Hammering a metal into foil **(P)** v. Water vaporizing **(P)** 11. Label the heating curve below using the key in the box to the right. 12. Identify the separation technique that would be most effective for each example listed below (Choices are filtration (F), evaporation (E), decantation (De), distillation (Di), or chromatography (C)). 13. Classify each of the following diagrams as either an element, a compound, a homogenous mixture, or a heterogenous mixture. +-----------------------------------+-----------------------------------+ | **Diagram** | **Classification and Reasoning** | +===================================+===================================+ |  | - This is an example of a | | | \_\_\_**[compound]{.underline | | | }**\_\_\_\_\_\_\_\_\_\_\_\_ | | | | | | - I know this because | | | \_\_\_**[the molecules are | | | evenly]**\_ | | | \_\_\_\_**[distributed and | | | look to be | | | chemically]**\_\_ | | | \_\_\_\_ | | | \_\_\_ [ **to each | | | other**]\_\_\_\_\ | | | _\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ | | | \_\_\_\_\_\_\_\_\_ | +-----------------------------------+-----------------------------------+ | | - This is an example of an | | | \_\_\_\_\_\_\_**[element]{.un | | | derline}**\_\_\_\_\_\_\_\_\_\_ | | | | | | - I know this because | | | \_\_\_**[only one type of | | | atom]**\_\_\_\_ | | | \_\_\_\_**[is | | | shown]**\_\_\_\_\ | | | _\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ | | | \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ | | | \_\_\_\_\_\_\_\_\_\_\_\_\_\_\ | | | _\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ | | | \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\ | | | _\_ | +-----------------------------------+-----------------------------------+ |  | - This is an example of a | | | \_\_**[heterogenous | | | mixture]**\_\_\_ | | | | | | - I know this because | | | \_\_**[there are different | | | ratios]** \_\_ | | | \_\_**[of the molecules in | | | the mixture based | | | on]** \_\_\_\_ | | | \_\_**[where a sample is | | | taken]**\_\_\_\_\ | | | _\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ | | | \_\_ | +-----------------------------------+-----------------------------------+ | | - This is an example of a | | | \_\_**[homogenous | | | mixture]**\_\_\_\ | | | _ | | | | | | - I know this because | | | \_\_\_\_\_\_**[all of the | | | atoms]** | | | \_\_\_\_\_\_\_ \_\_\_\_**[are | | | equally distributed | | | throughout | | | the]**\_\_\_\_\_\ | | | _\_ | | | \_\_\_\_**[mixture]{.underlin | | | e}**\_\_\_\_\_\_\_\_\_\_\_\_\_\_\ | | | _\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ | | | \_\_\_\_\_\_ | +-----------------------------------+-----------------------------------+ |  | - This is an example of a | | | \_\_**[heterogenous | | | mixture]**\_\_\_ | | | | | | - I know this because | | | \_\_\_\_\_**[the two | | | different]** | | | \_\_\_\_[**substances are not | | | equally | | | distributed**] | | | \_\_\_\_ [ ] | | | \_\_\_\_**[and form | | | layers]**\_\_\_\_ | | | \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\ | | | _\_\_\_\_ | +-----------------------------------+-----------------------------------+ 14. Explain to me the difference between heat and temperature. **Heat transfers energy while temperature is a physical quantity that measures the average kinetic energy** **[Unit 4: The Periodic Table]** 15. Fill in the table below. **Group** **Period** **Chemical Family** ---- --------------- ------------ --------------------------- Sr **2** **5** **Alkaline Earth Metals** Na **1** **3** **Alkali Metals** He **18 or 8a** **1** **Noble Gas** Br **17 or 17a** **4** **Halogen** Ag **11** **5** **Transition Metal** 16. Using the information given, fill in the table below. **N^3-^** **Barium-115** **Sn** ------------------- ----------- ---------------- --------- Period **2** **6** **5** Group **15** **2** **14** Atomic \# **7** **56** **50** \# of Protons **7** **56** **50** \# of Neutrons **10** **59** **69** Mass \# **14** **115** **119** \# of Electrons **10** **56** **50** Valence Electrons **5** **2** **4** Core Electrons **2** **54** **46** 17. Use a red pen to draw arrows over the Periodic Tables for which way each of the trends **[increases]**.  18. Arrange the following in increasing size (smallest to largest). w. Al, Mg, P, Cl \_\_\_**[Cl]**\_\_\_ \ 21. For each element below, indicate the number of valence electrons, the most likely charge that it's ion will assume, and whether the ion would be a cation or anion. Element \# of Valence Electrons Most Likely Ion Charge Cation or Anion? --------- ------------------------- ------------------------ ------------------ Sr **2** **2+** **Cation** Al **3** **3+** **Cation** S **6** **2-** **Anion** Br **7** **1-** **Anion** Na **1** **1+** **Cation** 22. Write the standard notation and shorthand notation electron configuration of each of the elements below. Cl Standard Notation **Cl:** **1s^1^2s^2^2p^6^3s^2^3p^5^** -------- -------------------- --------------------------------------- Shorthand Notation **Cl: \[Ne\] 3s^2^3p^5^** Na Standard Notation **Na: 1s^1^2s^2^2p^6^3s^1^** Shorthand Notation **Na: \[Ne\]3s^1^** Li^+^ Standard Notation **Li^+^: 1s^2^** Shorthand Notation **Li^+^: \[He\]** Mg^2+^ Standard Notation **Mg^2+^: 1s^2^2s^2^2p^6^** Shorthand Notation **Mg^2+^: \[Ne\]** S^2-^ Standard Notation **S^2-^:1s^2^2s^2^2p^6^3s^2^3p^6^** Shorthand Notation **S^2-^: \[Ar\]** 23. Determine which element is represented by the following electron configurations by writing the element's atomic symbol and the number of valence electrons it has. c. 1s22s22p2 **C Valence Electrons= 4** d. 1s22s22p63s23p64s23d104p1 **Ga Valence Electrons= 4** e. 1s22s22p63s23p64s2 **Ca Valence Electrons= 2** f. \[Ar\] 4s^1^ **K Valence Electrons= 1** g. \[Ne\] 3s23p3 **P Valence Electrons= 5** **[Unit 5: Chemical Bonding]** 24. Fill in the table below by classifying the given compound as either ionic or covalent and then either writing the chemical formula or IUPAC name of the given compound. **Ionic or Covalent?** **Chemical Formula** **IUPAC Name** ------------------------ ---------------------- -------------------------- **Ionic** AlBr~3~ **Aluminum bromide** **Ionic** **Fe(NO~2~)~3~** Iron (III) nitrite **Ionic** **Ca~3~N~2~** Calcium nitride **Ionic** AgNO~3~ **Silver nitrate** **Ionic** (NH~4~)~3~PO~4~ **Ammonium phosphate** **Ionic** **Mg(ClO~4~)~2~** Magnesium perchlorate **Covalent** N~2~O~4~ **Dinitrogen tetroxide** **Ionic** **Ga~2~S~3~** Gallium sulfide **Ionic** Zn(OH)~2~ **Zinc hydroxide** **Ionic** **K~2~(SO~3~)** Potassium sulfite **Covalent** **AsCl~3~** Arsenic trichloride **Ionic** **PbCl~2~** Lead(II) chloride **Ionic** Al~2~O~3~ **Aluminum oxide** **Covalent** **SF~6~** Sulfur Hexafluoride 25. Draw the **[Lewis Dot Diagram]** for each of the following elements in the boxes below. **Aluminum** **Silicon** **Magnesium** ------------------------ ------------- ------------------------   **Nitrogen** **Fluorine** **Krypton** -------------- ------------------------ -------------  26. Based off the chemical formula given, determine the total number of valence electrons in the compound and then draw the compound's Lewis Structure. **Chemical Formula** **Total Valence Electrons** **Lewis Structure** ---------------------- ----------------------------- ------------------------ H~2~ **2**  F~2~ **14** O~2~ **12**  HCl **10** HBr **8**  H~2~O **8** H~2~Se **8**  NH~3~ **8** CH~4~ **8**  CCl~4~ **32** 27. Explain the difference between the dash and dots in a Lewis Structure. **Dashes equal 2 valence electrons and demonstrate a bond between compounds to share electrons while dots represent single valence electrons which are transferred between compounds.** 28. How many electrons fulfill the octet rule? Are there any exceptions to this rule? **8 make an octet! However Hydrogen and Helium do not need an octet, they only need 2 valence electrons in their outer shell to be stable.**