CHEMISTRY UNIT TWO INTERACTIVE STUDY GUIDE ANSWERS PERIODIC TABLE (Chapter 7) 1. Elements in the same vertical column on the periodic table belong to the same group/family. 2. Elements in the same horizontal row on the periodic table belong to the same period. 3. Elements that are unreactive are called noble gases or inert. 4. Mendeleev s periodic table was useful because it a. had elements arranged by atomic number b. had no empty spaces c. show the atomic number of the elements d. allowed for the prediction of the properties of missing elements 5. An element that is very reactive is most likely a member of the a. noble gases b. alkali metals c. transition metals d. actinides 6. Which of the following items is not found on the periodic table? a. the atomic number of each element b. the name of each element c. the date that each element was discovered d. the atomic mass of each element 7. Which of the following statements about elements is true? a. Every element occurs naturally. b. All elements are found in their uncombined form in nature. c. Each element has a unique atomic number. d. All of the elements exist in approximately equal quantities. 8. Which of the following statements about the periodic table is false? a. There are more metals than nonmetals on the periodic table. b. Atoms of elements in the same group have the same number of electrons in their outer shell. c. The elements on the far left of the periodic table are nonmetals d. Elements are always arranged by increasing atomic number. 9. How was Moseley s basis for arranging the elements different from Mendeleev s? Moseley arranged elements by increasing atomic number. Mendeleev arranged elements by increasing atomic mass. 10. What is the periodic law? The periodic law states that the properties of elements repeat in a regular pattern as a function of atomic number.
11. Could a new element be discovered that would be placed between two consecutive known elements on the periodic table? Explain. No; the atomic number of each element on the periodic table increases by one proton, so there is no room for other elements in between known elements. 12. Identify each element: a. This metal is very reactive, has properties similar to those of magnesium, and is in the same period as bromine. calcium b. This nonmetal is in the same group as lead. carbon c. This metal is the most reactive metal in its period. It cannot be found uncombined in nature. Each atom of the element contains 19 protons. potassium CHEMICAL BONDING (Chapter 8) 1. Looking at the following label them a metal (M), nonmetal (NM), metalloid (ML): a. Oxygen NM b. Beryllium M c. Sodium M d. Sulfur NM e. Silicon ML 2. Ionic compounds are a combination of metal (M, NM) and nonmetal (M, NM). Covalent compounds are mostly a combinations of nonmetal/metalloid (M, NM) and nonmetal M, NM). 3. List 3 properties of ionic compounds Hard, brittle, forms crystals, high melting point, high boiling point, conduct electricity when in solution 4. List 3 properties of covalent compounds. Low melting point, low boiling point, do not conduct electricity in solution 5. Looking at the following compounds, label if it makes a covalent or ionic bond: a. NaCl ionic b. CO covalent c. SiO2 covalent d. H2O covalent e. BeF2 ionic 6. Draw electron dot diagrams for the following elements: B Se Ar Be 7. Draw an atomic model for the following atoms. Mg S (mass # = 24) (mass # = 34)
8. What is a metallic bond? Force that holds atoms together in a metallic substance 9. Write the formulas or name for the following compounds (BE SURE TO KNOW IF IT S AN IONIC OR COVALENT BOND BEFORE YOU DECIDE WHICH RULES TO USE!) a. Silicon tetraoxide: SiO4 b. Diphosphorous trichloride: P2Cl3 c. Trihydrogen bromide: H3Br d. N3F2: trinitrogen diflouride e. Li2S: lithium sulfide f. SiO2: slilcon dioxide 10. Find the formula for the following ionic compounds: a. Lewis dot b. Show e- transfer c. All oxidation # add to zero d. Chemical formula e. Name Aluminum & Oxygen: Strontium & Bromine: 11. Find the formula for the following covalent compounds: a. Lewis dot b. Circle shared pairs of e- c. Structural formula d. Chemical formula e. Name Carbon & Sulfur: Nitrogen & Oxygen: 12. What is a diatomic molecule and give three examples of these.
Two atoms bonded together; H2, O2, Cl2, I2 13. What is a metallic bond? Force that holds atoms together in a metallic substance 14. List 3 properties of metallic bonds. ductility, thermal and electrical conductivity, opacity, and luster, free moving electrons CHEMICAL REACTIONS (Chapter 9) Balance the equations below and label the type of reaction Type of reaction 1) C3H8 + 5 O2 3 CO2 + 4 H2O Combustion 2) FeCl3 + 3 NaOH Fe(OH)3 + 3 NaCl Double Replacement 3) 4 P + 5 O2 2 P2O5 Synthesis 4) 2 Na + 2 H2O 2 NaOH + H2 Single Replacement 5) 2 Ag2O 4 Ag + O2 Decomposition 6) S8 + 12 O2 8 SO3 Synthesis 7) 2 HCl + CaCO3 CaCl2 + H2O + CO2???? Answer the questions below: 1. What is a chemical reaction and what happens to the properties of the reactants compared to the properties of the products? A chemical reaction is when bonds are broken, atoms rearrange, and new bonds form. New substance(s) are created with new and different properties than the reactants. 2. What signs indicate that a chemical reaction may have occurred? Gas production, energy change, color change, odor change 3. What is the true indicator that a chemical reaction has definitely occurred? A new substance with new properties 4. What is an exothermic reaction? Give 2 examples. Releases energy; fire, glowstick 5. What is an endothermic reaction? Give 2 examples. Absorbs energy; photosynthesis, ice pack 6. What is the law of conservation of energy? Energy cannot be created or destroyed 7. What is a chemical formula and what does the subscript represent? Symbols and numbers that describe the atomic content of matter
8. What is the difference between a reactant and a product? Reactant materials before a reaction Products materials after a reaction 9. What is the law of conservation of mass? Mass cannot be created or destroyed 10. When balancing an equation, can you change the subscripts? Why or why not? NO! By changing the subscript, you are changing the entire substance and it s properties! Read the word equation. Write out the equation then balance it. Watch out for the diatomic super 7 (in which case write as H2, I2, O2, Br2, Cl2, N2, & F2.) Also be careful of ionic compounds, use the short cut and get the correct subscripts. Metals by themselves are just that (Ex: lead is Pb). 11. Aluminum Bromide** and chlorine gas* react to form aluminum chloride** and bromine gas*. 2AlBr3 + 3Cl2 2AlCl3 + 3Br2 12. Sodium phosphate, Na3PO4, and calcium chloride** react for form calcium phosphate, Ca3(PO4)2 and sodium chloride**. 2Na3PO4 + 3CaCl2 6NaCl + Ca3(PO4)2 13. Potassium metal and chlorine gas* combine to form potassium chloride**. 2K + Cl2 2KCl