Circle the Alphabet Segment of Your Last Name : A-G H-L M-P Q-Z

Chem 451 (Spring-2007)

Exam 1 (100 pts)

Name: ------, Clid #: ------

LAST, First

Circle the alphabet segment of your Last Name: A-G H-L M-P Q-Z

Please answer the following questions:

Part I: Multiple Choices (21 pts: 7 @ 3 pts). Please circle the ONE best answer:

1. What is the IUPAC name of the complex [Pt(en)(H2O)Cl3]Cl

a) Aquatrichloro(ethylenediamine)platinum(IV) chloride

b) Aquatrichloro(ethylenediamine)platinate(IV) chloride

c) Platinum(IV)aquatrichloro(ethylenediamin) chloride

d) Aqua(ethylenediamine)trichloroplatinum(IV) chloride

1. What is the point group of trans-dichlorodiamineplatinum(II)?

a) D2h b) Td

c) C2vd) C2h

1. Which one of the elements W, Os, Hg and Au has the highest melting point:

a) Wb) Os c) Hg d) Au

4. Arrange the elements Ba, W, Os and Au in order of decreasing their densities (highest =

1& lowest = 4):

a) Ba > W > Os > Au b) Au > Os > W > Ba

c) Os > W > Au > Ba d) W > Os > Au > Ba

5. How many planes of symmetry do F2C=O, HNF2 and OF2 possess?

a) 2, 1, 1, respectivelyb) 2, 0, 1, respectively

c) 3, 1, 2, respectivelyd) 2, 1, 2, respectively.

6. Consider the octahedral trans-[Co(NH3)4Cl2]+ ion; to what symmetry operation is C42 equivalent?

a) C2 b) σh c) σv d) C3

1. Which of the following structural formula and name is incorrect?

a) Ni(CO)4: tetracarbonylnickel(II)

b) [Cr(H2O)6]Cl3: hexaaaquachromium(III) chloride

c) Ir(NH3)3Br3: triaaminetribromoiradium(III)

d) Na2[Ni(CN)4]: sodium tetracyanonickel(II)

Part II. (58 pts) Transition Metals:

The following two graphs show the variation in ionization energies (IE) with atomic numbers:

1. (10 pts) The first two IEs of the first row of d-block elements increase only slightly with increasing atomic number, but the third IE increases strongly from Sc to Mn, then drops back at Fe, only it increases again to Zn. Explain these observations.

2. (16: 2 @ 8 pts) Give a brief account for each of the following:

a) Variation of the atomic radii across the d-block elements and the 4f elements (lanthanides).

b) The Transamericium and transuranium elements

3. (16 pts: 2 @ 8 pts each) Explain the following observations:

a) In aqueous solutions the most stable oxidation state of neodymium, Nd is +3 but for

its actinide counterpart, uranium, U, oxidation state +6 is most stable.

b) The uniformity in the properties of the lanthanides and the great diversity observed in the chemistry of actinides.

4. (16 pts) Predict the probable structure (bond order & electron configuration) and magnetic properties for the following metal-metal bonded tetragonal-prismatic complexes:

a) [Mo2(CH3CO2)4] b) [Ru2(CH3CO2)4(O=C(CH3)2)2]

Part III. (21 pts) Symmetry and Point Group

1. (6 pts) (a) What symmetry elements do BF3 and NF3 have in common and (b) not have in common?

1. (15 pts: 3 @ 5 pts) What is the point group for each of the three isomers of tribromobenzene?

(a) (b) (c)

You will have 55 minutes to complete this exam.

The exam has 4 pages plus Periodic Table

When you are told to do so, tear off the Periodic Table cover sheet and use as required during exam.

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