Chem 100/121 Exam 2 Name______________ Date_______________ You may use a calculator for this exam. The conversion table from the back of the book is included on the last page of the exam, and you may use the periodic table posted in the room. 1. A. In what ways are isotopes alike? 2 points Answer:________________________________________________ B. In what ways are they different? 2 points Answer:________________________________________________. 2. How many neutrons are present in each of the following: 119 92 Sn : 2 pts Zr : 3 List the electron sublevels from 1s through 5s in order of increasing energy. 3 points Answer:________________________________________________. 5 Write the electronic configuration (1s# etc.) for: 10 points A. Br-:______________________________________________________. B. K+ :______________________________________________________ C. N : ______________________________________________________ D. Ar: _________________________________________________________________ E. Mg: _________________________________________________________________ 6. For each of the following pairs, circle the more electronegative element: N C Cs Ca Cl Br P O 8 pts 7. Rank the following five elements according to the radii of their atoms, from smallest to largest: K, Cs, F, B, Ca, N 3 pts Answer:_________________________. 8. How many valence electrons do each of the following atoms have? 8 pts As _______ Si ________ O ________ Li ________ 9. Draw the Lewis dot diagram for CO2 4 pts 10. (10 pts) Use VSEPR theory to predict the geometry of the central atom in each of the following (your answer should be one of the following: linear, triangular planar, triangular planar/bent, tetrahedral, tetrahedral/triangular pyramidal, or tetrahedral/bent) a) H3O+ b) CH4 c) BH3 d) BeH2 e) NH3 11. (8 pts) How many electrons must be gained or lost for the following to achieve a noble gas electron structure? a. a chloride anion b. a phosphorus atom c. a lithium atom d. a magnesium atom ______ 12. (2 pts) Element Z reacts with oxygen to form the compound Z2O3 and is a member of the fourth period of the periodic table. Identify this element. 13. (6 pts) Use Lewis structures and arrows to show the electron transfer that enables these ionic compounds to be formed: a. MgO b. NaBr c. SiH4 14. Write the formula of the compound that would be formed between the given elements. 4 points A. Ca and N____________________ B. Sr and O______________________ C. Y and S_____________________ D. Mg and Cl_____________________. 15. Name the following binary compounds: A. Al2S3_______________________ B. N2O5_________________________ C. S2Cl2_______________________ D. NiS___________________________ 2 points 16. Write formulas for the following binary compounds: 4 points A. Iron(III) sulfide_________________ B. Titanium(III) oxide_________________ C. Lead (II) fluoride______________ D. Copper (II) phosphide_________________. 17. Name each of the following 4 points A. CaCO3 ___________________________ B. Li2SO4 _________________________ C. K2Cr2O7___________________________D. Ca(MnO4)2 ________________________ 18. Write formulas for the following: 6 points A. Sulfuric acid ______________________ B. Hydrochloric acid _________________ E. Cupric bromide ____________________ F. Titanous chloride ___________________ I. Lithium iodate _____________________ J. Mercurous sulfate _______________ 19. Name the following: 4 points A. HNO3(aq) ___________________________ B. HClO (aq) _________________________ 2 C. H O ____________________________ D. HClO (aq) ________________________ 2 2 20. Determine the oxidation number of the element underlined. A. H2SO4 B. MnO2 C. Ca3(PO4)2 D. Co2(NO3)6 8 points