Name: Period: Date: Hybrid Chemistry Regents Prep Ms. Hart/Mr. Kuhnau UNIT 2: BONDING Lecture 2.4: Free- Response Bonding Practice Do Now: By the end of today, you will have an answer to: How do we solve bonding free- response questions? 1. What is the IUPAC name for PbO? 2. Which atom has the weakest attraction for the electrons in a bond with an H atom? (1) Cl atom (3) O atom (2) F atom (4) S atom 3. Explain, in terms of electronegativity, why the bond between HCl is more polar than the bond between HI? 4. Circle all of the elements that attains a stable valence electron configuration by bonding with another atom. neon chlorine oxygen helium copper boron hydrogen radon calcium argon FREE- RESPONSE TIPS 1. STAY CALM! 2. READ QUESTION FIRST. Do NOT read long passages before reading the questions. 3. Underline the words after IN TERMS OF. 4. Annotate above what you just underlined any related terms or understandings. 5. Circle what you are looking for. 6. READ THE PASSAGE (if necessary). AFTER WALKING THROUGH EACH QUESTION, YOU SHOULD HAVE ONE THING YOU ARE EXPLAINING UNDERLINED AND HOW YOU ARE EXPLAINING IT CIRCLED. SIMPLICITY IS KEY. DO NOT MAKE UP SCIENCE. 1
Name: Period: Date: Hybrid Chemistry Regents Prep Ms. Hart/Mr. Kuhnau Review Topic 1: Lewis- Dot Diagrams Step 1: Always create the Lewis- Dot Diagrams of the individual atoms first. Step 2: Make a box for the missing electrons (remember, a stable shell = 8 electrons). Step 3: Connect electrons to the box on a central element. Cross out the electron. Step 4: Redraw the diagram using lines (a line = 2 electrons). 1. O 2 2. N 2 3. NH 3 4. CH 4 Review Topic 2: Criss Cross Method (ONLY for IONIC compounds) Step 1: Write the ionic charges of each element (roman numerals = charge) Step 2: Cross them so that the metal s charge is written to the right and below the nonmetal and the nonmetal s charge is written to the right and below the metal. Example: Al 3+ O 2 Al 2 O 3+ Step 3: Remove the + s and s. Step 4: Reduce to lowest terms if necessary. Remove the number 1. 1. Magnesium sulfide 2. Copper (II) chloride 3. Sodium nitrate Review Topic 3. Reverse Criss Cross Method (ONLY for IONIC compounds) Step 1: Add in the charges by each subscript (if there is no subscript, we know it is 1.) Step 2: Cross them so that the metal s subscript is written as the nonmetal s charge and vice versa. Example: Al 2 O 3+ Al 3+ O 2 1. NaCl 2. CrCl 3 3. LiOH 4. Al 2 (SO 3 ) 3 2
Review Topic 4: Naming Ionic Compounds Step 1: Write the name of the metal. Step 2: Write the name of the nonmetal. Step 3: Substitute ide at the end of the nonmetals name. Step 4: Transition metals (found in groups 3-12) need to have a roman numeral for their charges. 1. NaCl 2. CrCl 3 3. LiOH 4. Al 2 (SO 3 ) 3 Review Topic 5: Electronegativity, Polarity, and Symmetry Polar Nonpolar 1. Which phrase describes the distribution of charge and polarity in a CH 4 molecule? (1) Symmetrical and polar (3) asymmetric and polar (2) Symmetrical and nonpolar (4) asymmetric and nonpolar 2. Which Lewis electron- dot diagram represents a molecule having a nonpolar covalent bond? 3. Which element has the lowest electronegativity value? (1) F (3) Cl (2) Fr (4) Cr 4. Which diagram best represents a polar molecule? (1) (2) (3) (4) 5. Which structural formula represents a linear nonpolar molecule containing two polar bonds? (1) (2) (3) (4) 3
CW#2.4 FREE RESPONSE PRACTICE Base your answers to questions 1 and 2 on the information below. Ozone, O 3 (g), is produced from oxygen, O 2 (g), by electrical discharge during thunderstorms. The unbalanced equation below represents the reaction that forms ozone. 1. Identify the type of bonding between the atoms in an oxygen molecule. 2. Explain, in terms of electron configuration, why an oxygen molecule is more stable than an oxygen atom. 3. What is the total number of electron pairs shared between the carbon atom and one of the oxygen atoms in a carbon dioxide molecule? 4. Explain, in terms of subatomic particles, why the radius of a chloride ion is larger than the radius of a chlorine atom. 5. Explain, in terms of valence electrons, why the bonding in magnesium oxide, MgO, is similar to the bonding in barium chloride, BaCl 2. Base your answers to questions 6 through 8 on the information below. In 1864, the Solvay process was developed to make soda ash. One step in the process is represented by the balanced equation below. NaCl + NH 3 + CO 2 + H 2 O! NaHCO 3 + NH 4 Cl 6. Write the chemical formula for one compound in the equation that contains both ionic and covalent bonds. 7. Explain, in terms of electronegativity difference, why the bond between hydrogen and oxygen in a water molecule is more polar than the bond between hydrogen and nitrogen in an ammonia molecule. 8. Draw a Lewis- dot diagram for the reactant nitrogen in equation. 9. Explain, in terms of electronegativity difference, why the bond in a molecule of HF is more polar than the bond in a molecule of HI. 4
Name: Period: Date: Hybrid Chemistry Regents Prep Ms. Hart/Mr. Kuhnau 2.4 HW MULTIPLE CHOICE PRACTICE: 1. What is the IUPAC name for the compound ZnO? (1) zinc oxide (3) zinc peroxide (2) zinc oxalate (4) zinc hydroxide 2. Which element has the lowest electronegativity value? (1) F (3) Cl (2) Fr (4) Cr 3. An ionic bond can be formed when one or more electrons are (1) equally shared by two atoms (2) unequally shared by two atoms (3) transferred from the nucleus of one atom to the nucleus of another atom (4) transferred from the valence shell of one atom to the valence shell of another atom 4. An ion that consists of 7 protons, 6 neutrons, and 10 electrons has a net charge of (1) 4- (3) 3+ (2) 3- (4) 4+ 5. Which Lewis electron- dot diagram represents a molecule having a nonpolar covalent bond? 9. What is the chemical formula of iron(iii) sulfide? (1) FeS (3) FeSO 3 (2) Fe 2 S 3 (4) Fe 2 (SO 3 ) 3 10. What is the total number of electron pairs shared between the two atoms in an O 2 molecule? (1) 1 (3) 6 (2) 2 (4) 4 11. When an atom of lithium loses an electron, the atom becomes a (1) negative ion with a radius smaller than the radius of the atom (2) negative ion with a radius larger than the radius of the atom (3) positive ion with a radius smaller than the radius of the atom (4) positive ion with a radius larger than the radius of the atom 12. A molecular compound is formed when a chemical reaction occurs between atoms of (1) chlorine and sodium (2) chlorine and yttrium (3) oxygen and hydrogen (4) oxygen and magnesium 13. Which element has atoms with the greatest attraction for electrons in a chemical bond? (1) Beryllium (3) lithium (2) Fluorine (4) oxygen 6. The bond between which two atoms is most polar? (1) Br and Cl (3) I and Cl (2) Br and F (4) I and F 7. In the formula X 2 (SO 4 ) 3, the X represents a metal. This metal could be located on the Periodic Table in (1) Group 1 (3) Group 13 (2) Group 2 (4) Group 14 8. Which atom in the ground state requires the least amount of energy to remove its valence electron? (1) lithium atom (3) rubidium atom (2) potassium atom (4) sodium atom 14. A metal, M, forms an oxide compound with the general formula M 2 O. In which group on the Periodic Table could metal M be found? (1) Group 1 (3) Group 16 (2) Group 2 (4) Group 17 15. What is the net charged of an ion that has 8 protons, 9 neutrons, and 10 electrons? (1) 1+ (3) 1- (2) 2+ (4) 2-16. Which molecule has a nonpolar covalent bond? 5
Base your answers to questions 26 on the information below. 17. Explain, in terms of molecular polarity, why hydrogen chloride is more soluble than methane in water at 20 degrees Celsius and standard pressure. Base your answers to questions 27 and 28 on the information below. During a fireworks display, salts are heated to very high temperatures. Ions in the salts absorb energy and become excited. Spectacular colors are produced as energy is emitted from the ions in the form of light. The color of the emitted light is characteristic of the metal ion in each salt. For example, the lithium ion in lithium carbonate, Li 2 CO 3, produces a deep- red color. The strontium ion in strontium carbonate, SrCO 3, produces a bright- red color. Similar calcium chloride is used for orange light, sodium chloride for yellow light, and barium chloride for green light. 18. Write the formula for the salt used to produce green light in a fireworks display. 19. Identify the two types of chemical bonds found in the salt used to produce a deep- red color. 20. Draw a Lewis electron- dot diagram for CF 4. 21. The solvay process is a multistep industrial process used to produce washing soda, Na 2 CO 3 (s). In the last step of the Solvay process, NaHCO 3 (s) is heated to 300 degrees Celsius, producing washing soda, water, and carbon dioxide. Write the IUPAC name for washing soda. 6